diff --git a/Foundation/include/Poco/URI.h b/Foundation/include/Poco/URI.h
index 944b84cc5..4aa36fde8 100644
--- a/Foundation/include/Poco/URI.h
+++ b/Foundation/include/Poco/URI.h
@@ -246,10 +246,12 @@ public:
 		/// URI-encodes the given string by escaping reserved and non-ASCII
 		/// characters. The encoded string is appended to encodedStr.
 		
-	static void decode(const std::string& str, std::string& decodedStr);
+	static void decode(const std::string& str, std::string& decodedStr, bool plusAsSpace = false);
 		/// URI-decodes the given string by replacing percent-encoded
 		/// characters with the actual character. The decoded string
 		/// is appended to decodedStr.
+		/// When plusAsSpace is true, non-encoded plus signs in the query are decoded as spaces.
+		/// (http://www.w3.org/TR/html401/interact/forms.html#h-17.13.4.1)
 
 protected:
 	bool equals(const URI& uri) const;
diff --git a/Foundation/src/URI.cpp b/Foundation/src/URI.cpp
index cb30ca429..d0626f03a 100644
--- a/Foundation/src/URI.cpp
+++ b/Foundation/src/URI.cpp
@@ -595,14 +595,18 @@ void URI::encode(const std::string& str, const std::string& reserved, std::strin
 }
 
 	
-void URI::decode(const std::string& str, std::string& decodedStr)
+void URI::decode(const std::string& str, std::string& decodedStr, bool plusAsSpace)
 {
+	bool inQuery = false;
 	std::string::const_iterator it  = str.begin();
 	std::string::const_iterator end = str.end();
 	while (it != end)
 	{
 		char c = *it++;
-		if (c == '%')
+		if (c == '?') inQuery = true;
+		// spaces may be encoded as plus signs in the query
+		if (inQuery && plusAsSpace && c == '+') c = ' ';
+		else if (c == '%')
 		{
 			if (it == end) throw SyntaxException("URI encoding: no hex digit following percent sign", str);
 			char hi = *it++;
diff --git a/Foundation/testsuite/src/URITest.cpp b/Foundation/testsuite/src/URITest.cpp
index bcbfeff51..ca6433754 100644
--- a/Foundation/testsuite/src/URITest.cpp
+++ b/Foundation/testsuite/src/URITest.cpp
@@ -767,6 +767,26 @@ void URITest::testOther()
 }
 
 
+void URITest::testEncodeDecode()
+{
+	std::string str;
+	URI::encode("http://google.com/search?q=hello+world#frag ment", "+#?", str);
+	assert (str == "http://google.com/search%3Fq=hello%2Bworld%23frag%20ment");
+
+	str = "";
+	URI::encode("http://google.com/search?q=hello+world#frag ment", "", str);
+	assert (str == "http://google.com/search?q=hello+world#frag%20ment");
+	
+	str = "";
+	URI::decode("http://google.com/search?q=hello+world#frag%20ment", str, true);
+	assert (str == "http://google.com/search?q=hello world#frag ment");
+	
+	str = "";
+	URI::decode("http://google.com/search?q=hello%2Bworld#frag%20ment", str);
+	assert (str == "http://google.com/search?q=hello+world#frag ment");
+}
+
+
 void URITest::setUp()
 {
 }
@@ -788,6 +808,7 @@ CppUnit::Test* URITest::suite()
 	CppUnit_addTest(pSuite, URITest, testNormalize);
 	CppUnit_addTest(pSuite, URITest, testResolve);
 	CppUnit_addTest(pSuite, URITest, testSwap);
+	CppUnit_addTest(pSuite, URITest, testEncodeDecode);
 	CppUnit_addTest(pSuite, URITest, testOther);
 
 	return pSuite;
diff --git a/Foundation/testsuite/src/URITest.h b/Foundation/testsuite/src/URITest.h
index 0895403b8..fb5f63153 100644
--- a/Foundation/testsuite/src/URITest.h
+++ b/Foundation/testsuite/src/URITest.h
@@ -53,6 +53,7 @@ public:
 	void testNormalize();
 	void testResolve();
 	void testSwap();
+	void testEncodeDecode();
 	void testOther();
 
 	void setUp();