British Liberal Democrat leader Nick Clegg today dismissed Labour promises to overhaul the voting system, likening them to a “consumer guarantee from Del Boy”.
Gordon Brown is expected to use a keynote campaign speech to highlight Labour’s plans for constitutional reform - including a referendum on introducing a form of proportional representation for Westminster.
The proposal has widely been seen as an attempt to woo the Liberal Democrats in the event of a hung parliament - although Labour’s plans do not go as far as the LibDems would like.
However Mr Clegg insisted that neither Labour nor the Conservatives could be trusted when it came to issues of constitutional reform.
"They have systematically at every turn blocked every single reform - they have blocked party funding reform, they have blocked reform on lobbying," he told the BBC Radio 4 Today programme.
“Believing any promises from them on political reform is a bit like accepting a consumer service guarantee from Del Boy - don’t believe it, they are trying to treat you like fools.”
The prime minister and the Tory leader will both keep up the hectic early pace of campaigning with a series of engagements straight after their Commons showdown.
Having already journeyed to Birmingham and Leeds yesterday, Mr Cameron is set to travel to Bolton this afternoon where he will visit a large business to underline his opposition to Labour’s National Insurance rise.
Mr Brown is expected to limit himself to London but keep up the interaction with voters after a trip out to key battleground seats in Kent yesterday.
In London this afternoon, he is expected to address constitutional reform in his speech, including his commitment to a fully elected House of Lords. It was reported that he would also promise to introduce four-year fixed-term parliaments which would remove from prime ministers the power to call general elections.
The Sun's daily YouGov poll today put the Tories on 40 per cent (down one), Labour on 32 per cent (up one) and the Liberal Democrats on 17 per cent (down one).
PA