A senior Conservative peer from Norfolk has said the coalition's plans for reforming the House of Lords will leave Parliament fighting itself in the courts.

Baroness Shephard, who has been at the forefront of the battle against reform, warned that government plans were poorly drafted as they were presented in Westminster yesterday.

The proposals contain a specific commitment to the 1911 and 1949 Parliament Acts which enshrine the Commons as the most powerful chamber, able to force its will upon the Lords.

But Baroness Shephard claimed Lords politicians in the future will be able to argue that the Parliament Acts do not apply to the new Lords chamber.

She told the EDP: 'I have no doubt that under such a proposal, if there was a conflict between an elected House of Lords and an elected House of Commons it would end up in the courts.

'The new House of Lords would be able to say that the Parliament Acts do not apply to the new kind of chamber that would be established by this reform.'

Under the plans the new Lords would be an 80% elected chamber, with a slimmed down membership falling from 800 to 450.

Hereditary peers would be completely removed from the Lords and the first elected members introduced in tranches of 120 at each of the next three general elections, with the process of change completed by 2025.

Elected members would serve for a single 15-year term and rather than a salary would instead receive �300 for each day they attend on which they would be taxed.

The plan was a key Liberal Democrat policy outlined in the coalition agreement that formed the current government, but up to 100 Conservative MPs have now said they may oppose the changes.

David Cameron yesterday insisted that voters were behind the change and warned his MPs they would face sanction if they opposed the government's will.

Meanwhile Baroness Shephard said that if the Commons appeared divided over the issue then she and other peers in the House of Lords would do everything they could to attack the reforms.

On official estimates, the new House of Lords will end up costing the taxpayer an extra �150m per five-year period than at present.

And it is also expected that �3.8 million will be spent on a publicity drive to raise voters' awareness of the new elections, which will cost around �85.7 million per time.

'The government should bring forward a properly drafted, properly thought out proposal that shows they have considered the constitutional and cost implications.

'Most of all the public should be asked what they think in a referendum.'