Tomlinson: "Show abuses that go on in the British secret service"

Richard Tomlinson was served with a High Court injunction on his arrival in New Zealand. It prohibits him from saying anything of his work with MI6, Britain's external intelligence agency.

The injunction was jointly applied for by the British and New Zealand Governments.

The Foreign Office in London said the measure was intended to prevent Mr Tomlinson from making "damaging disclosures."

A spokesman said: "The effectiveness of the secret service depends crucially on its ability to protect the secrecy of its operations and the identity of those who choose to offer it intelligence, sometimes at great personal risk to themselves.

"There is no question of taking this action to stifle criticism of the Secret Intelligence Service."

Last weekend Mr Tomlinson was briefly detained in France along with another former intelligence agent, David Shayler, who is also wanted by Britain.

Mr Shayler is now facing extradition after being arrested at the weekend.

Mr Shayler has been on the run since he gave accounts of his work for the security service to a British newspaper.

He was also due to publish information about MI5's operations on the Internet.

'Secret service excesses'

Mr Tomlinson, aged 35, told Television New Zealand he would write a book.

He said: "I want to show some of the excesses of the British secret service."

Spy writer Rupert Allason: The injunction will be an effective gag

The New Zealand-born former MI6 agent was jailed in Britain for one year last year for passing secret information to a publisher. He was released earlier this year on probation.

Mr Tomlinson was arrested at a Paris hotel last Friday at the request of the British authorities, who believed he was planning a book on his activities in Britain's foreign intelligence service.

It is believed Mr Tomlinson was released because French police did not have strong enough grounds to detain him.

Both Mr Tomlinson and Mr Shayler had reportedly intended to open a Website hitting out at the inefficiency of British intelligence.

Wadham: will fight an 'unjust extraditiion'

Mr Shayler's lawyer John Wadham has travelled to Paris at the start of a legal battle to prevent his extradition.

Mr Wadham, director of civil rights group Liberty, is hoping to meet him in the French jail were he is being held but needs permission from the French judge in charge of the case before visiting his client.

He also plans to meet Mr Shayler's partner, Annie Machon, and the French lawyers dealing with the case.

Mr Wadham said he intended to ensure that Mr Shayler's defence team would have the best possible strategy for fighting the "unjust" extradition.

It is likely to be several months before Mr Shayler finds out if he will be sent to the UK to stand trial for allegedly revealing details about his former employers, MI5.

'Inhumane conditions'

Mr Shayler's brother, Jeremy, has joined those speaking out against the behaviour of the UK Government

In a letter to a newspaper, he said his brother was suffering "inhumane conditions" at the hands of the British and French Governments.

"He has been imprisoned for criticising inefficiency within MI5; he has not been charged with any crime.

"Quite simply my brother is being made an example of," he said