Cameron: I will be as tough as Thatcher

David Cameron will today promise to be as tough as Margaret Thatcher in taking on Britain's "vested interests" if they seek to block the reforms and spending cuts he would make as prime minister.

The Tory leader will recall Baroness Thatcher's battles over curbing trade union power, privatising state-run industries and selling council houses to tenants. He will pledge to emulate her strong leadership as he brands Gordon Brown as "weak" over the British Airways and rail strikes.

Speaking in London, Mr Cameron will declare he is ready for a "fight" with the teaching unions, local authorities and educational establishment over Tory plans to allow charities, churches, private schools and parents to set up new state-funded schools and restore classroom discipline. He also signalled a readiness to face down unions gearing up to oppose spending and job cuts in the public sector. "I have no doubt that some of the changes we want to make will mean facing down some really powerful vested interests," he will say.

A government led by him would represent "the national interest" rather than "pandering to vested interests" like the unions as Labour is doing, he will declare. As well as exploiting Labour's headache over the pre-election transport strikes, the speech is designed to put flesh on the bones of his "vote for change" pitch following criticism that they have not answered the "change to what?" question. His praise for Lady Thatcher will reassure Tory traditionalists with doubts about Mr Cameron, who has distanced himself from her remark that "there is no such thing as society".

"Political leadership means standing up for the people – and standing up to those who act against their interests," he will say. "Put simply, you can't change Britain unless you take on vested interests. Change doesn't just happen. Change isn't easy. It's hard because there will always be people who want to preserve the status quo even when it isn't working in everyone's interests."

Mr Cameron will say: "Margaret Thatcher's government was defined by taking the side of the people against the powerful, the vested interest – those whose survival depended on keeping things as they were."

In contrast, the Tory leader will claim, Mr Brown diluted planned reforms to schools and hospitals because he was "too terrified of upsetting the union barons, losing their votes and their money". The Government gave in to vested interests by backing a third runway at Heathrow Airport, ensuring light-touch regulation in the City of London and refusing to split the banks' high street and investment operations.

Mr Cameron will say: "It's the Conservative Party that has the leadership, the energy, the strength of character to stand up to vested interests and make change happen." Branding Labour as "feeble and weak", Mr Cameron will argue: "The style we offer is different – strong, resolute, taking on those who block progress so we see change through. From weakness to strength. From elite power to people power. From vested interests to the national interest. That's the change we offer."