Home Secretary Theresa May today argued that the United Kingdom should withdraw from the European Convention on Human Rights, even while remaining a member of the European Union.

Mrs May argued that EU membership made the UK more secure from crime and terrorism, but that the UK had "forgotten how to lead" in Europe and had to re-assert itself in order to force change within the Union.

Too often the UK's "collective posture" was to blame Europe for its problems, and the country had to have more confidence to get things done, rather than be "shouting from the sidelines".

The Home Secretary admitted that being in the EU made it harder to control the volume of immigration, while insisting that the UK was able to control its border by blocking entry to terrorists.

She described the post-war legal order as one where countries "cede sovereignty in a controlled way" by co-operating to prevent a greater loss of sovereignty through military conflict or economic decline. The question was not whether the UK could survive outside the EU, but whether it was better off in or out. She had concluded it was a matter of "hard-headed national interest" to remain in, based on security, trade and prosperity.

Leaving the EU could also threaten the future of the UK, through another Scottish independence referendum.

However Mrs May maintained that the power of the European Parliament and the European Court of Justice should be reduced, and opposed further enlargement by admitting countries like Serbia and Albania.

Regardless of the outcome of the referendum, she said she still believed the UK should leave the European Convention of Human Rights, saying that it bound the hands of Parliament and added "nothing to our prosperity". Reform of human rights laws would only be brought about by leaving the ECHR and the jurisdiction of its court.

"It wasn't the European Union that delayed for years the extradition of Abu Hamza, almost stopped the deportation of Abu Qatada, and tried to tell Parliament that – however we voted – we could not deprive prisoners of the vote. It was the European Convention on Human Rights", she stated.

Present Government policy is to repeal the Human Rights Act, which enables Convention rights to be directly enforceable in the British courts, but not to withdraw from the Convention itself.

Mrs May however commented: "Human rights were not invented in 1950, when the Convention was drafted, or in 1998, when it was incorporated into our law through the Human Rights Act.

"This is Great Britain – the country of Magna Carta, parliamentary democracy and the fairest courts in the world – and we can protect human rights ourselves in a way that doesn't jeopardise national security or bind the hands of Parliament."

Lord Falconer, the former Lord Chancellor and current Shadow Justice Secretary, described Mrs May's comments as "ignorant, illiberal, and misguided", adding: "She is sacrificing Britain's 68-year-old commitment to human rights for her own miserable Tory leadership ambitions."

An attempt by the EU as an institution to accede to the Convention ran into trouble when the Court of Justice held some of the terms of the Accession Convention to be incompatible with aspects of the EU Treaties, but it is still widely believed that it would be incompatible with EU membership for a member state to withdraw from the Convention.