The Government has rejected criticism over its efforts to engage with British Muslims after the 7 July bombings.
Sadiq Khan, MP for Tooting, said members of the Muslim working groups set up by ministers "feel let down" and called for a public inquiry into the suicide bombings.
The Department for Communities and Local Government maintained that many community-led projects were under way to help "root out extremism".
Speaking at a Fabian Society conference on "Being a British Muslim" last night, Mr Khan said: "What has happened to all the good ideas? Why hasn't an action plan been drawn up with time lines?
"There has been limited progress but there is an air of despondency. Only three recommendations have been implemented, and group members feel let down.
"I worry that the Government might become the Duke of York - marching all these talented British Muslims up the hill of consultation and dialogue only to march them down again as very little appears to have changed.
"We need to return to these ideas and this strategy. We need to show that it was not a short-term PR exercise, and that the ideas have not been shelved."
A spokesman for the Department for Communities and Local Government said: "We are committed to working in partnership with Muslim communities to root out extremism and tackle the causes of radicalisation amongst a minority of our young people.
"The 64 recommendations developed by the Preventing Extremism Together groups represent a unique achievement.
"The practical suggestions the groups made were primarily for Muslim communities to take forward, although some will be delivered in partnership with Government, and some will be for Government to lead. To suggest that none of them are being delivered undermines the hard work that the groups have put in to tackling extremism."
The seven working groups set up by the Government in the wake of the London bombings reported last November.
They called for a public inquiry and were scathing about planned new terror laws. Lord Ahmed, one of the chairs of the working groups then called for the Government to prove the exercise was not a "one-off event".Reuse content