BUCKINGHAM Palace jubilee concert will go ahead as planned – despite the fierce blaze that tore through a part of the building at the height of the rehersals.

BUCKINGHAM Palace jubilee concert will go ahead as planned – despite the fierce blaze that tore through a part of the building at the height of the rehersals.

Smoke and flames billowed from the roof of the palace's West Terrace as around 100 firefighters, many wearing breathing apparatus, fought to stop it from spreading.

The fire, which lasted about an hour, took hold as final rehearsals for the Queen's Golden Jubilee pop concert took place in the gardens below.

No members of the Royal Family were present — and today's pop concert is set to go ahead as planned, organisers said.

Members of the Royal Family were kept informed as the incident developed, and a spokesman for the Prince of Wales said: "He was shocked but relieved that no one had come to any harm."

It was thought to have been the first time Buckingham Palace had been evacuated since the Second World War.

Hundreds of tourists visiting the gates of the palace, which is playing host to the Golden Jubilee celebrations this weekend, watched as up to 12 fire engines arrived.

Scotland Yard said the fire was reported at 6.42pm and the palace was evacuated as a precaution.

Buckingham Palace spokeswoman Penny Russell-Smith said: "Smoke was seen coming from the roof of the East Gallery, which is a large corridor which leads from the ballroom to the state room."

Speaking from outside the palace, she said it was too early to say how the fire had started, though police say no foul play is suspected.

Hundreds of people, including pop stars, TV crews and technicians, were moved to the tennis courts from the gardens as they rehearsed for tonight's pop concert. Among them were Queen guitarist Brian May, Eric Clapton and female trio Atomic Kitten.

The fire service said four people who had been working on the palace roof had to be escorted down to safety by police and firemen.

A spokesman also said valuable artefacts were being removed from areas near the fire are in order to keep them safe from any damage.

Steve Newman, a firefighter on the scene, said: "In the course of fire-fighting four people were escorted from the roof. They were staff who were guided down through the house. They were staff working on the roof.'

Mr Newman said that as far as he was aware there were no casualties and no reported need for medical attention.

He added: "We will be here as long as there is any danger, we don't know how much damage there has been but we have been assisting in salvaging valuable artefacts as a precautionary measure.'

One firefighter was taken to hospital after suffering cuts and bruises around an eye injured during the fire.

Access to the palace and its gardens has been unprecedented in recent days in the run-up to the jubilee celebrations.

A massive music auditorium with stage and stands had been constructed in the gardens.

On Saturday night, more than 12,000 people attended a classical music concert in the gardens and the same number are due to attend the pop concert tonight.

The fire is a further blow to the Queen in a year of personal tragedy following the death of her mother and her sister, Princess Margaret.

The fire is believed to have started in a corridor between the ballroom and the State Rooms.

The State Rooms form the heart of the working palace and are used regularly by the Queen and members of the Royal family for official and State entertaining.

The ballroom is the largest multi-purpose room in Buckingham Palace and was opened in 1856 to celebrate the end of the Crimean War.

It is along the East Gallery, from where smoke was seen billowing, that the Queen and her State guests proceed to the ballroom for the State Banquet normally held on the first day of a State visit.

The ballroom is the regular venue for Investitures.

The fire revived memories of the horrific blaze which caused £40million of damage to Windsor Castle in 1992.

Royal author Robert Lacey said he was outside Buckingham Palace when he saw the fire brigade outside.

"I was going past and I saw the fire brigade. I thought it must be a false alarm but I was obviously wrong."

He added: "It's hardly the Windsor Castle fire. There has been quite a history of fires at royal palaces, with Hampton Court in the 1980s and Windsor Castle in 1992 but this doesn't sound as if it is on quite the same scale.

"Anyone familiar with the place will be astonished with the way it has been opened and transformed in the last few weeks, with airport security devices and 12,000 people trooping through.

"The fire could be something to do with the extra lighting and wiring or a careless cigarette smoker. Buckingham Palace has been turned into a public palace.

"In my experience the palace staff are extremely efficient. I'm sure the Queen was informed immediately it happened and kept in touch with everything."

Sir Neil Cossons, chairman of English Heritage, said: "We don't know how bad the damage is but English Heritage will offer all the help it can to the royal household."

English Heritage advised the royal household on restoration of Windsor Castle following the fire.