Brown prepares to tie the knot

The couple will hold a party after their honeymoon

Chancellor Gordon Brown and his long-time girlfriend Sarah Macaulay are to be married on Thursday in a family service in his Dunfermline East constituency.

The pair will be married in small, private ceremony at St Peter's Church in Inverkeithing, with Mr Brown's brother John acting as best man.

Then there will be a small reception for family and friends before setting off on honeymoon.

We are absolutely delighted and very happy

Gordon Brown

The newly-weds are expected to fly to Cape Cod in Massachussets, the area which is home to America's first political family, the Kennedys.

The wedding announcement was delivered in a surprise statement on Wednesday evening from Mr Brown's special adviser, ending speculation over when the couple would tie the knot.

Prime Minister Tony Blair and his wife Cherie will not be attending the ceremony, but were among the first to offer their congratulations.

A spokeswoman for the Blairs said they were "very happy for the chancellor and Sarah Macaulay".

The couple, who are said to be "absolutely delighted", will be holding a party for friends and colleagues when they return from honeymoon in September.

Mr Brown's brother arrives for the wedding

It emerged that Mr Brown had proposed to Miss Macaulay in January and a date for the wedding had been set soon afterwards.

Mr Brown, 49, said after the news was announced: "We are absolutely delighted and very happy."

Mr Brown and Ms Macaulay, 40, met six years ago when her PR firm, Hobsbawn and Macaulay Communications, was involved in arranging Labour party events. They began dating in 1996.

Despite widespread speculation about their relationship, there was no hint that wedding plans were being drawn up before Wednesday's surprise statement.

It emerged that the announcement of the impending wedding had been displayed in the normal way in the parish where the ceremony would take place.

Police outside Mr Brown's home in North Queensferry

Mr Brown has had several serious relationships over the years, but it has been suggested that his passion for politics has previously hindered his personal life.

Liberal Democrat leader Charles Kennedy and a spokesperson for the Conservative Party also offered congratulations to the couple.

"I wish them both a happy day and a wonderful life together," Mr Kennedy said.

A Conservative Party spokesman said: "The party wishes Gordon and Sarah every happiness for the future."