Former Northern Ireland Secretary who paved the way for the Good Friday Agreement

Born: September 11, 1929;

Died: June 25, 2016

LORD (Patrick) Mayhew of Twysden, who has died aged 86, was a former Conservative Cabinet minister who as Northern Ireland secretary helped craft the Downing Street Declaration of 1993 which led to the IRA ceasefire eight months later and paved the way for the Good Friday Agreement.

As a minister and law officer in Margaret Thatcher’s government, he was also involved in a number of controversies around government secrets, including the Westland scandal which led to the resignation of Michael Heseltine and almost brought down the government. Lord Mayhew was also in charge when the civil servant Sarah Tisdall was prosecuted for leaking details of cruise missile deployments and he led the vain attempt to prevent the publication of Spycatcher, the memoirs of the former spy Peter Wright.

Although much of the credit eventually went to others, Lord Mayhew saw his time as Northern Ireland as the height of his career and coveted the job for a long time, partly because of his own background as the son of a mother who came from an old Anglo-Irish family in Cork (he also spent much of his youth in the republic).

He was educated at Tonbridge and Balliol College, Oxford, where he studied law and was deeply involved in politics from an early stage – he was elected unopposed as president of the Oxford Union debating society and also became president of the university Conservative Association.

After national service with the Royal Dragoon Guards, he was called to the Bar in 1955 before fighting Dulwich for the Conservatives in 1970 and losing narrowly to Labour. Four years later, he tried again and became MP for Tunbridge Wells in Kent, where he remained the member for 23 years.

At first, he struggled to adapt to the House of Commons and some found his haughty lawyer manner a turn-off. He also realised that he would have to stop treating the Commons as if it were a Court of Appeal.

“I think the law is a bad training for politics,” he once said. “It diminishes hunch but it does teach you the importance of words and their use. For the first two years, every time I spoke in the Commons I made a court of appeal speech and spoke as if I had a bad smell under my nose.”

He was eventually recognised for his potential when Margaret Thatcher came to power in 1979 and appointed him to the Department of Employment as a parliamentary undersecretary, where he worked on trade union reform.

After the Tories’ 1983 landslide, he then became solicitor general and was quickly embroiled in the Tisdall affair. She had been accused of leaking information to the Guardian and was prosecuted in 1984 under the Official Secrets Act and sentenced to six months in prison.

Two years later, Lord Mayhew was at the heart of the infamous Westland affair which almost brought down the government. It centred on the proposed sale of the British helicopter company – Lord Heseltine, the defence secretary, favoured a European consortium; Leon Brittan, the trade secretary, with the support of the Prime Minister, preferred the American bidder Sikorsky.

The scandal broke after Lord Mayhew wrote to Heseltine saying that there were what he called material inaccuracies in his case for the European option and the letter was leaked. Lord Mayhew was furious and demanded an inquiry and was said to have threatened to have the police sent into Downing Street. Leon Brittan eventually fell on his sword, although it was widely suspected that Thatcher herself had authorised the leak.

After the 1987 election, Lord Mayhew was promoted to attorney general and led the ultimately disastrous attempt to suppress the publication of Spycatcher. Lord Mayhew said the government was seeking to uphold the principle that anyone who works for the security services is bound by a lifelong duty of secrecy but his attempts at suppression, first in the Australian courts and then in the UK, failed.

After John Major succeeded Thatcher in 1990, Lord Mayhew remained a central figure in government. He was a member of the war cabinet during the First Gulf War but was hopeful of being appointed Northern Ireland Secretary, a post he was eventually given in 1992.

The appointment did not look particularly promising to either side at first, but Lord Mayhew’s pragmatism eventually began to make progress. All party talks took place in Dublin and in 1992, he said that if the IRA renounced violence, Sinn Fein could take part.

The following year saw the issuing of the Downing Street Declaration, formulated by John Major and then Irish taoiseach, Albert Reynolds, and the following September the IRA declared a ceasefire. In 1995, Lord Mayhew also became the first secretary of state to meet Gerry Adams.

After Labour came to power in 1997, Lord Mayhew advised the new secretary of state Mo Mowlam. He received a life peerage and from 2000 chaired the Prime Minister’s committee on business appointments.

In December 2012 David Cameron praised Lord Mayhew in the House of Commons as he made a statement on Sir Desmond de Silva’s report into the nature and extent of state collusion in the murder of the human rights lawyer Patrick Finucane.

Mr Cameron told the Commons de Silva had found the then attorney general Lord Mayhew deserved "significant credit for withstanding considerable political pressure designed to ensure" that some prosecutions did not go ahead.

In a statement, Lord Mayhew’s family said he had died peacefully at his home in Kent after living with cancer and Parkinson's for several years.

The former Cabinet minister is survived by his wife Jean Mayhew, their four sons and their families.