Leicester Square comes to life as the sun goes down

London's West End theatres are also keeping a close eye on the situation in the UK, fearing a knock-on effect.

But a trip around the tourist haunts of the capital shows that many are heeding the advice of world leaders and carrying on with "normal" life.

A heaving Leicester Square on a mild October day was testament to this.

The magnet for tourists continued to teem with those soaking up a slice of London life.

The queues for ticket huts selling discounted seats to the top shows were as long as ever.

Waiting patiently in line were the Herman family from Ohio, who were seven days into their three-week holiday to the UK.

We have been planning this holiday for several years and we were not going to let what has happened at home ruin it

Steve Herman American tourist

Despite stories of holidays being cancelled left, right and centre they were not tempted to scrap their trip.

"We have been planning this holiday for several years and we were not going to let what has happened at home, however tragic, ruin it," said father Steve Herman.

"If I thought there was a risk I would not have travelled with my wife and two children but I believe it is probably safer to fly now than ever before because security is so tight."

As day turns to night the bright lights of Leicester Square continued to attract crowds.

For John and Pat Bonds from Boston, Massachusetts, this is their fourth trip to the UK in 10 years.

I haven't noticed much difference in the amount of people in London - it always seems to be busy

John Bond American tourist

Mr Bonds said he thought London still seemed busy.

But he added: "Our flight over was emptier than usual though, and I do know of people back home that put off travelling because they became scared of flying."

The buskers appeared to be doing a roaring trade with audiences taking in the free entertainment, but there were markedly less people around than during the day.

School parties made up the majority of those milling around, also making the most noise.

What was noticeable is that many of the restaurants looked half empty.

One café owner, who wished to remain nameless, said trade had been slow in recent weeks but he was unsure whether this was because of fears over the economy or a reaction to the US attacks.

Buskers are still drawing in the crowds in Leicester Square

Lone traveller Andrea Pickett from Houston, Texas, said she had been surprised at just how expensive it was to stay in London.

"The best thing about London are the museums and art galleries, and at least they are free," she commented.

Moving on to the heart of theatreland, it was packed with people, a mixture of tourists and those leaving work.

Coaches also lined the streets bringing visitors from across the UK to the big shows.

At the Adelphi Theatre the production of Chicago continues to attract big audiences.

I think people are trying to get on with their lives and show the terrorists that they can't stop anyone having a good time

Adele Bridges New Yorker in London

The auditorium was almost full on the night in question, with just a handful of empty seats.

A snapshot poll of theatre-goers suggested that queuing up during the day at the discount booths was a popular method of snapping up bargain tickets.

Adele Bridges from New York is spending a year in the UK and had not noticed fewer tourists in the capital since 11 September.

"I genuinely think people are trying to get on with their lives and show the terrorists that they can't stop anyone having a good time," she said.

As the actors took their final bows the streets once again buzzed as the crowds poured out onto the streets.

Some restaurants are struggling to bring in custom

But it did not take long for them to empty as people headed home.

Once again restaurants appeared to be struggling to pull in the after-theatre diners as waiters stood idle in some of the establishments around the West End.

Although some are still pulling in the punters, many restaurants are attracting the after-work crowd rather than tourists.

By 0030 BST the streets were more or less deserted and there was hardly a tourist to be found, just a handful of workers making their way home after an evening out.

The final word goes to a group of them waiting to catch a tube home.

"What is going on in the world at the moment is depressing enough without giving up having fun."