A minute's silence is to be held across Britain to mark the first anniversary of the 11 September attacks on the United States, the government has announced.

Centrepiece of the commemoration will be a service at St Paul's Cathedral in central London, which will begin at 1315 BST and fall silent 31 minutes later, at 1346 BST.

It will be the exact time a year earlier that the attacks began, with American Airlines Flight 11 crashing into the north tower of New York's World Trade Center.

The invited multi-faith 2,000-strong congregation will include the Prince of Wales, US ambassador William Farish, families of the British victims, senior government figures and representatives of the emergency services, charities and business.

Workers across the UK are also expected to observe the silence, with offices, factories, shops and television and radio networks falling quiet.

Public announcements

The BBC and ITV will screen images of remembrance services in London and New York without commentary.

The silence will also be observed at seven major airports including Heathrow, Stansted, Gatwick and Manchester.

Public announcements will be made at supermarkets and major train stations.

And trading will halt in high street shops and department stores.

Colleagues died

The government's announcement may also lead to similar arrangements in Whitehall departments, schools, courts and churches.

Hundreds of firefighters intend to observe the silence outside their stations in honour of their 343 colleagues who died in the attacks.

The City - where many firms which lost employees in the World Trade Center have offices - is also planning to mark the anniversary.

The London Stock Exchange, the London Metal Exchange, the London International Financial Futures and Options Exchange and Lloyd's of London all plan to fall silent.

The most poignant tribute will be held at financial services firm Cantor Fitzgerald, which lost 700 employees.