The Lord Chancellor will set himself on a collision course with solicitors when he announces plans today to press ahead with a radical revamp of the ?2 billion legal aid scheme.

As hundreds of solicitors mount public protests this week throughout England and Wales, Lord Falconer of Thoroton will say that he is determined to proceed with controversial plans that could drive hundreds of solicitors out of legal aid work.

In an interview with The Times, he tells solicitors to ?knuckle down? to make the reforms work, saying that they have no option but to go along with the biggest overhaul of the scheme in 50 years.

Lord Falconer, in the Government?s final response to consultation on the reforms, will concede some changes to the timing of implementation, with a six-month delay for some plans. But his message is that the package will go ahead, despite a warning from the Law Society, the professional body for solicitors in England and Wales, that solicitors will respond ?with their feet?.

Predicting a ?winter of discontent?, a spokesman for the Law Society said: ?Solicitors are very, very angry. They have called a special general meeting, for January, the first in five years, which is a measure of their feeling.?

An estimated 800 firms could be forced to leave criminal legal aid work, the society says; and four in five towns in England and Wales will be left without lawyers handling children?s cases.

Lord Falconer agreed that solicitors would not be happy, although he said that he had listened to their case. ?There is considerable concern about this . . . and they?ve just got to knuckle down and work out how it will work in practice.?

The pressure, he said, was for more money for criminal legal aid. But limits had to be set. More money would be spent in family cases, but with no rise in the overall budget because of the significant rise in children?s care cases, which were now a drain on the system.

He accepted also that the reforms, which introduce fixed fees rather than hourly rates and a market for legal aid with solicitors bidding for contracts, would mean fewer law firms.

It was crucial, he said, for solicitors to reorganise themselves if they were to be a thriving profession. ?If we continue to spend as much on a fragmented profession and don?t reward those firms who do criminal cases in a way that focuses most of the money on the case and as little as possible on the overheads, then we won?t be able to continue to serve people as we have in the past.?

In a series of minor concesssions, the Lord Chancellor said that plans for new fee rates in Crown Court trials for barristers would take effect as planned next April, but he is to delay for six months new fee rates for solicitors? Crown Court work so that these can be adjusted between larger and smaller cases. Fees for police station work would also go ahead at that date. But he emphasised that the overall level of funding would stay the same.

Plans for competitive tendering, with solicitors bidding for legal aid contracts, will be brought forward from April 2009 to October 2008; and he agreed a six-month delay on fees for family cases until October next year for a ?radical revision? of the proposals to ensure that more complex cases are rewarded; and a ?more equitable distibution between types of case?. But the Lord Chancellor said: ?I am absolutely clear that there will be no more money.?