diff --git a/Code/Mantid/Framework/Algorithms/CMakeLists.txt b/Code/Mantid/Framework/Algorithms/CMakeLists.txt
index 6188e2c9c65b3ad5c8d08770ccb28ada8d30f052..6caf0a9385bbd52c5770222d08499d38156a9408 100644
--- a/Code/Mantid/Framework/Algorithms/CMakeLists.txt
+++ b/Code/Mantid/Framework/Algorithms/CMakeLists.txt
@@ -29,6 +29,7 @@ set ( SRC_FILES
src/ChangePulsetime.cpp
src/CheckWorkspacesMatch.cpp
src/ChopData.cpp
+ src/ClearMaskFlag.cpp
src/CloneWorkspace.cpp
src/CommutativeBinaryOperation.cpp
src/ConjoinWorkspaces.cpp
@@ -238,6 +239,7 @@ set ( INC_FILES
inc/MantidAlgorithms/ChangePulsetime.h
inc/MantidAlgorithms/CheckWorkspacesMatch.h
inc/MantidAlgorithms/ChopData.h
+ inc/MantidAlgorithms/ClearMaskFlag.h
inc/MantidAlgorithms/CloneWorkspace.h
inc/MantidAlgorithms/CommutativeBinaryOperation.h
inc/MantidAlgorithms/ConjoinWorkspaces.h
@@ -458,6 +460,7 @@ set ( TEST_FILES
ChangePulsetimeTest.h
CheckWorkspacesMatchTest.h
ChopDataTest.h
+ ClearMaskFlagTest.h
CloneWorkspaceTest.h
CommutativeBinaryOperationTest.h
CompressedRebinTest.h
diff --git a/Code/Mantid/Framework/Algorithms/inc/MantidAlgorithms/ClearMaskFlag.h b/Code/Mantid/Framework/Algorithms/inc/MantidAlgorithms/ClearMaskFlag.h
new file mode 100644
index 0000000000000000000000000000000000000000..1b6dc9e9a162239a981be5dd4e6ff6c3556c5a72
--- /dev/null
+++ b/Code/Mantid/Framework/Algorithms/inc/MantidAlgorithms/ClearMaskFlag.h
@@ -0,0 +1,56 @@
+#ifndef MANTID_ALGORITHMS_CLEARMASKFLAG_H_
+#define MANTID_ALGORITHMS_CLEARMASKFLAG_H_
+
+#include "MantidKernel/System.h"
+#include "MantidAPI/Algorithm.h"
+
+namespace Mantid
+{
+namespace Algorithms
+{
+
+ /** ClearMaskFlag : TODO: DESCRIPTION
+
+ Copyright © 2013 ISIS Rutherford Appleton Laboratory & NScD Oak Ridge National Laboratory
+
+ This file is part of Mantid.
+
+ Mantid is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ Mantid is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+ File change history is stored at: <https://github.com/mantidproject/mantid>
+ Code Documentation is available at: <http://doxygen.mantidproject.org>
+ */
+ class DLLExport ClearMaskFlag : public API::Algorithm
+ {
+ public:
+ ClearMaskFlag();
+ virtual ~ClearMaskFlag();
+
+ virtual const std::string name() const;
+ virtual int version() const;
+ virtual const std::string category() const;
+
+ private:
+ virtual void initDocs();
+ void init();
+ void exec();
+
+
+ };
+
+
+} // namespace Algorithms
+} // namespace Mantid
+
+#endif /* MANTID_ALGORITHMS_CLEARMASKFLAG_H_ */
\ No newline at end of file
diff --git a/Code/Mantid/Framework/Algorithms/src/ClearMaskFlag.cpp b/Code/Mantid/Framework/Algorithms/src/ClearMaskFlag.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..8a638f237be10e34f447fe5aa71fc76766f83b71
--- /dev/null
+++ b/Code/Mantid/Framework/Algorithms/src/ClearMaskFlag.cpp
@@ -0,0 +1,72 @@
+/*WIKI*
+This algorithm clears the mask flag/bit on all spectra of a workspace. It does not restore masked data.
+*WIKI*/
+
+#include "MantidAlgorithms/ClearMaskFlag.h"
+
+namespace Mantid
+{
+namespace Algorithms
+{
+
+ using namespace API;
+ using Kernel::Direction;
+
+ // Register the algorithm into the AlgorithmFactory
+ DECLARE_ALGORITHM(ClearMaskFlag)
+
+
+
+ //----------------------------------------------------------------------------------------------
+ /** Constructor
+ */
+ ClearMaskFlag::ClearMaskFlag() {}
+
+ //----------------------------------------------------------------------------------------------
+ /** Destructor
+ */
+ ClearMaskFlag::~ClearMaskFlag() {}
+
+ //----------------------------------------------------------------------------------------------
+ /// Algorithm's name for identification. @see Algorithm::name
+ const std::string ClearMaskFlag::name() const { return "ClearMaskFlag";};
+
+ /// Algorithm's version for identification. @see Algorithm::version
+ int ClearMaskFlag::version() const { return 1;};
+
+ /// Algorithm's category for identification. @see Algorithm::category
+ const std::string ClearMaskFlag::category() const { return "Utility";}
+
+ //----------------------------------------------------------------------------------------------
+ /// Sets documentation strings for this algorithm
+ void ClearMaskFlag::initDocs()
+ {
+ std::string summary("Delete the mask flag/bit on all spectra in a workspace.");
+ this->setWikiSummary(summary);
+ this->setOptionalMessage(summary);
+ }
+
+ //----------------------------------------------------------------------------------------------
+ /** Initialize the algorithm's properties.
+ */
+ void ClearMaskFlag::init()
+ {
+ declareProperty(new WorkspaceProperty<>("Workspace","",Direction::InOut), "Workspace to clear the mask flag of.");
+ }
+
+ //----------------------------------------------------------------------------------------------
+ /** Execute the algorithm.
+ */
+ void ClearMaskFlag::exec()
+ {
+ MatrixWorkspace_sptr ws = getProperty("Workspace");
+
+ // Clear the mask flags
+ Geometry::ParameterMap & pmap = ws->instrumentParameters();
+ pmap.clearParametersByName("masked");
+ }
+
+
+
+} // namespace Algorithms
+} // namespace Mantid
diff --git a/Code/Mantid/Framework/Algorithms/test/ClearMaskFlagTest.h b/Code/Mantid/Framework/Algorithms/test/ClearMaskFlagTest.h
new file mode 100644
index 0000000000000000000000000000000000000000..9ac858108b0fa9d5c951dd433032a32cec80f041
--- /dev/null
+++ b/Code/Mantid/Framework/Algorithms/test/ClearMaskFlagTest.h
@@ -0,0 +1,98 @@
+#ifndef MANTID_ALGORITHMS_CLEARMASKFLAGTEST_H_
+#define MANTID_ALGORITHMS_CLEARMASKFLAGTEST_H_
+
+#include <cxxtest/TestSuite.h>
+#include "MantidAlgorithms/ClearMaskFlag.h"
+#include "MantidDataObjects/Workspace2D.h"
+#include "MantidGeometry/Instrument.h"
+#include "MantidGeometry/Instrument/Detector.h"
+#include "MantidTestHelpers/ComponentCreationHelper.h"
+
+using namespace Mantid::API;
+using namespace Mantid::DataObjects;
+using namespace Mantid::Geometry;
+using Mantid::Algorithms::ClearMaskFlag;
+using Mantid::MantidVecPtr;
+
+class ClearMaskFlagTest : public CxxTest::TestSuite
+{
+public:
+ // This pair of boilerplate methods prevent the suite being created statically
+ // This means the constructor isn't called when running other tests
+ static ClearMaskFlagTest *createSuite() { return new ClearMaskFlagTest(); }
+ static void destroySuite( ClearMaskFlagTest *suite ) { delete suite; }
+
+
+ void test_Init()
+ {
+ ClearMaskFlag alg;
+ TS_ASSERT_THROWS_NOTHING( alg.initialize() )
+ TS_ASSERT( alg.isInitialized() )
+ }
+
+ void test_exec()
+ {
+ // create a workspace
+ const int numspec = 9;
+ const int nummask = 5;
+ Instrument_sptr instr = boost::dynamic_pointer_cast<Instrument>(ComponentCreationHelper::createTestInstrumentCylindrical(1, false));
+ Detector *d = new Detector("det",0,0);
+ instr->markAsDetector(d);
+
+ // create the workspace
+ MatrixWorkspace_sptr space = WorkspaceFactory::Instance().create("Workspace2D",numspec,6,5);
+ Workspace2D_sptr space2D = boost::dynamic_pointer_cast<Workspace2D>(space);
+ MantidVecPtr x,vec;
+ x.access().resize(6,10.0);
+ vec.access().resize(5,1.0);
+ for (int j = 0; j < numspec; ++j)
+ {
+ space2D->setX(j,x);
+ space2D->setData(j,vec,vec);
+ space2D->getSpectrum(j)->setSpectrumNo(j);
+ space2D->getSpectrum(j)->setDetectorID(j);
+ }
+ space->setInstrument(instr);
+ space->generateSpectraMap();
+
+ // set the mask on a bunch of spectra
+ Mantid::Geometry::ParameterMap& pmap = space->instrumentParameters();
+ for (int j = 0; j < nummask; ++j)
+ {
+ pmap.addBool(instr->getDetector(j)->getComponentID(), "masked", true);
+ }
+
+
+ // register the workspace in the data service
+ std::string wsName("ClearMaskFlagTest_WS");
+ AnalysisDataService::Instance().addOrReplace(wsName, space);
+
+ // run the algorithm with nothing masked
+ ClearMaskFlag alg;
+ TS_ASSERT_THROWS_NOTHING( alg.initialize() )
+ TS_ASSERT( alg.isInitialized() )
+ TS_ASSERT_THROWS_NOTHING( alg.setPropertyValue("Workspace", wsName) );
+ TS_ASSERT_THROWS_NOTHING( alg.execute(); );
+ TS_ASSERT( alg.isExecuted() );
+
+ // retrieve the workspace from data service. TODO: Change to your desired type
+ Workspace2D_sptr ws;
+ TS_ASSERT_THROWS_NOTHING( ws = AnalysisDataService::Instance().retrieveWS<Workspace2D>(wsName) );
+ TS_ASSERT(ws);
+ if (!ws) return;
+
+ // check the results
+ Instrument_const_sptr out_instr = ws->getInstrument();
+ for (int j = 0; j < numspec; ++j)
+ {
+ TS_ASSERT(!out_instr->isDetectorMasked(j));
+ }
+
+ // remove workspace from the data service.
+ AnalysisDataService::Instance().remove(wsName);
+ }
+
+};
+
+
+#endif /* MANTID_ALGORITHMS_CLEARMASKFLAGTEST_H_ */