It seems that numerous MP's have still not learnt their lesson about understanding what an acceptable expense is, as yesterday it was revealed that 237 MPs-more than a third of the Commons-put first class rail journeys on expenses.

The embarrassment of the expenses scandal seems to have worn off for some, as at least 20 MPs are enjoying first-class travel worth up to £14,000 a year each.

However what's more ludicrous is that they are getting away with it under a rule by parliamentary watchdog IPSA, which allows MPs to claim for any first-class fair costing less than an anytime standard open ticket-the most expensive available.

In theory an MP going from London to Newcastle is entitled to claim for a £255 first-class return. But he could make the same trip for just £110 in standard class.

The implication on taxpayers is that they are hit with an annual bill of more than £3million if all MPs go by this rule.

The Taxpayers' Alliance called for a ban on first class travel for all MPs last night.

A spokeswoman said: "It's disgraceful. Some MPs are not going along with the spirit of the changes to expenses." It was also revealed five MPs have earned £200,000 from outside interests since the election.