The government's plan to hold a referendum next May on changing the voting system could be blown off course by a vote in the House of Lords.

Defending the bill on the Today programme, Liberal Democrat Justice Minister Lord McNally said the changes, including redrawing boundaries to make them roughly equal sizes and cutting 50 MPs from the House of Commons, were a "minor adjustment" which would "get the wrinkles out of our system".

But former Labour Lord Chancellor Lord Falconer, who is leading opposition to the bill in the House of Lords, said the bill would lead to fewer back-benchers and therefore "a weaker House of Commons" and raised concerns over the .

He argued that the combination of boundary reform and the referendum on the Alternative Vote means the bill is a "hybrid" which should be referred to a Lord's committee for judgement - a move which could delay the AV referendum.

This, according to Lord McNally, was a lawyers' "wheeze" to try and delay the introduction of a fairer voting system.

"I'll see you in court Charlie," he said.

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