Sacked – and angry. New awkward squad is out to get the PM

After a bloody reshuffle, David Cameron is about to find former ministers lining up to attack his Government

A former minister sacked from the Cabinet is to spearhead a Tory opposition campaign against the Government's plans to build a high-speed rail link between London and Birmingham, amid growing signs that this week's reshuffle will intensify opposition to David Cameron and Nick Clegg on the Coalition benches.

Cheryl Gillan, who was dismissed as Welsh Secretary, said last night that she was determined to oppose the £32.7bn HS2 project, following her removal from the Government.

She is one of a series of newly sacked ministers who threaten trouble for the Coalition now they are free to oppose Government policy. They include Paul Burstow, the former Liberal Democrat Health minister, and Nick Herbert, the "Cameroon" former Home Office minister. Twenty-six ministers – 22 Conservatives and four Liberal Democrats – were returned to the Commons backbenches as the Coalition's leaders tried to inject younger blood into their team. Many of them could join the growing ranks of the "awkward squad", using their positions as former ministers to attack Coalition policies.

Mrs Gillan, who fought an unsuccessful battle to remain in post, told her local newspaper that she felt "liberated" to speak out against the HS2 project, which would cut through her Chesham constituency in Buckinghamshire.

"I know people in my constituency were frustrated with what they saw as a lack of action on my part and I completely understand that," she said.

Several remaining ministers with seats along HS2's planned route are known to share her views, but have been forced to curb their public criticism. Mrs Gillan's move will give fresh impetus to the anti-HS2 campaign at a moment when responsibility for the scheme has been taken over by a new Transport Secretary, Patrick McLoughlin.

Tory sources are braced for Mrs Gillan to speak out on the issue and also expect her to join the party's growing band of Eurosceptic critics.

But they expect Caroline Spelman – despite her dismay at being fired as Environment Secretary – and Sir George Young, the former Leader of the Commons, to remain loyal to the party leadership.

Mr Burstow said yesterday that he wanted to speak out about NHS plans to close his local A&E department. "Obviously if you are a minister you have no involvement in decisions affecting your constituency but this will take the target off my back and allow me to campaign against decision which I believe is flawed," he said.

Mr Burstow – who was in charge of social care in the Department of Health – also intends to speak out about the need to implement fully proposals by the Dilnot Commission to reform the way in which care for the elderly is paid for.

The plan now has the support of David Cameron but the Treasury is trying to ensure that the £2bn cost is met out of the existing NHS budget. "This is something I care passionately about and intend to challenge and question in Parliament," Mr Burstow said. "I will be saying more about it over the next few weeks."

Tory whips are most worried about Mr Herbert, who sprang the biggest surprise of the reshuffle when he resigned after missing out on promotion to the Cabinet.

He has kept a low profile since then, apart from saying in his resignation statement that he wanted to "focus on new ideas and protecting countryside". Several middle-ranking ministers were stunned to be sacked. They include Charles Hendry, the Energy minister, Tim Loughton, the Children's minister, Nick Gibb, an Education minister, and Peter Luff, a Defence minister.

The question for the party whips is whether their dismay will manifest itself in rebelling against the party line.

A source in the whips' office said: "Every reshuffle carried out by every Prime Minister causes problems. There will be the people in denial who didn't expect to be sacked. There will be those who actually did a good job and had to make for others. The trick is not to be bitter and try to channel their energy positively."

On the Liberal Democrat side, Sarah Teather, who was replaced as Schools minister, presents a potential opponent of party policy. Nick Harvey, who was removed as a Defence minister, is close to Mr Clegg and is expected to remain loyal. The fourth Liberal Democrat to bow out, Andrew Stunell, is expected to keep a low profile.

Rebels with a cause: The ministers turning on Cameron

Cheryl Gillan, Con (was Welsh Secretary)

Made little secret of her opposition to HS2 while still in the Government. She will now resist the scheme noisily and publicly. On the right of the party. A staunch Eurosceptic.

Rebel risk: **** (out of five)

Nick Herbert, Con (was Policing Minister)

Former Cameron close ally who quit after being passed over for promotion. Says he wanted to "focus on new ideas and protecting countryside". Believes Coalition proposals on gay marriage do not go far enough.

Rebel risk: *****

Gerald Howarth, Con (was Defence Minister)

Devoted Thatcherite and proponent of free-market economics, he is to be knighted. But his new status is unlikely to stop him from being in the thick of Europe rebellions or criticising cuts to military spending.

Rebel risk: ****

Paul Burstow, Lib Dem (was Health Minister)

Fell out with Clegg over the health reforms. He will fight plans to close his local A&E department and has vowed to speak out on the need to reform social care.

Rebel risk: ***

Sarah Teather, Lib Dem (was Schools Minister)

Provoked irritation within party leadership after going missing at contentious Commons votes. May now cause further headaches with criticism of policies promoted by Clegg loyalists.

Rebel risk: ****

Tim Loughton, Con (was Children's Minister)

Made no secret of his anger at being sacked, retweeting comments critical of his removal from Government. Recently attacked gay marriage proposals, saying marriage must only be between a "man and a woman".

Rebel risk: ***