Campaigners who have been protesting for three years that Norwich's assessment centre for disabled people does not have wheelchair access have spoken of their disbelief that the problem has still not been tackled.

Today's demonstration outside St Mary's House marked the third anniversary of a campaign by human rights group Equal Lives for a rethink over the situation.

Assessments to establish if somebody is 'fit for work' are carried out upstairs at the Duke Street centre, which makes it inaccessible to people in wheelchairs.

People in wheelchairs or who have restricted mobility are advised they must be able to walk downstairs in the event of an emergency, as the lift would be out of use.

They have previously been offered appointments at home or at assessment centres in areas including King's Lynn, Cambridge and Ipswich as an alternative.

A deal to use ground-floor rooms fell through last month, eight months after the government finally agreed to take action.

Mark Harrison, chief executive of Equal Lives said: 'I still can't believe that, after three years, we have still not resolved this issue. It seems common sense that it is not acceptable to have a disability assessment centre that disabled people can't get into. In spite of Ministerial assurances there is still no end in sight to this sorry saga.'

New private company – Maximus Health Services – has taken over responsibility for work capability assessments from Atos.

A DWP spokesman previously said the government was looking at a number of other options and would make a decision as soon as it could.

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March 2012 – A first protest is held at the Norwich office

February 2014 – Campaigners stage another protest outside the centre with people still being send hundreds of miles for appointments elsewhere.

June 2014 – Disabilities minister Mike Penning admits the situation is 'wholly unacceptable', and says he would be taking action to leave St Mary's House in Duke Street as soon as possible.

December 2014 – DWP says it is in the process of securing two ground floor assessment rooms. It is hoped that the new rooms – in addition to the current assessment rooms – should be ready for use early in the new year.

February 2015 - The DWP admits a hoped-for deal to allow access via ground floor rooms cannot be reached