Tony Blair's spokesman has dismissed criticism of the former prime minister's decision not to appear before MPs investigating the situation in Palestine.

The former Labour leader, now representative for the Middle East Quarter, was due to appear before the Commons international development committee next Thursday but his office has cancelled "without explanation".

Speaking to ePolitix.com, shadow international development secretary Andrew Mitchell said that the move was because the contrast between Blair and his successor in Number 10 "would be so awful", just as Gordon Brown was trying to re-launch his premiership after the elections.

Mitchell said: "I think that Tony Blair has cried off because the contrast between him and the current prime minister would be so great and so awful for Gordon Brown that Blair was probably asked not to attend."

Asked whether this amounted to "playing politics" with the situation in Palestine, he said: "Yes, I think it is a huge pity that Tony Blair is not going along to the select committee because this is a very important subject and Blair is the representative from the Quartet on the Middle East peace process and I think it is a very bad thing that he has snubbed the committee in this way. I think it is disgraceful."

However a spokesman for the former Labour leader said: "As we have discussed with the committee, Mr Blair is very happy to appear to talk about his work as Quartet representative helping the Palestinians to prepare for statehood as part of the international community's effort to secure peace.

"We have said he will do so in the next few weeks. However, he is unfortunately unable to do the suggested date as he has commitments out in the Middle East at that time in the run up to President Bush's visit, the World Economic Forum and the Palestine Investment Conference in May."

The spokesman also described Mitchell's comments as "depressingly pathetic".

In a separate ePolitix.com interview, Liberal Democrat chairman of the committee Malcolm Bruce said of the move that there was a "limit to how much messing about we can have".

Bruce said: "We put out a press notice last week saying that he was coming to give evidence and as soon as we did that his office rang us and said 'we can't come now'. They haven't given us an explanation.

"Our position is that we'd like the evidence so we can prepare the report so there is a limit to how much messing about we can have."

He added: "We think it is quite important - after all, the Department for International Development is funding the office of the Quartet so it is right and proper to hear exactly what he is doing."