The Home Affairs Select Committee has urged home secretary Alan Johnson to reconsider plans to allow hacker Gary McKinnon to be extradited to the US to stand trial.

McKinnon is something of a cause célèbre and has gathered support from a wide range of factions, although what extra impact the intervention of this group will have is yet to be seen, especially since repeated attempts to stop the extradition have been rebuffed.

Committee chairman Keith Vaz has written to Johnson saying the extradition should be blocked on humanitarian grounds. In his letter Vaz writes: “Because of Mr McKinnon's precarious state of mental health, the Committee is of the view that he should not be extradited to the USA and that you should exercise your discretion in this case.”

However, Johnson is unlikely to be moved. Earlier this week he said the decision to extradite, and the rules surrounding the practice, were fair.

This morning, a poster on the Free Gary campaign blog wrote, "Why is it so hard for this Labour government to admit that they are wrong?"

The blog's mission statement reads: "It seems only just that Gary should face any charges in a British court, and to serve any sentence, if he is found guilty, in a British prison."

McKinnon is accused of "the biggest military hack of all time", although he claims he was only looking for evidence of extra-terrestrials.