London had best brace itself because, with three vital points up for grabs when Norwich City play Fulham today, the Yellow Army is invading the capital.

With the Canaries looking to prevent their third season in the Premier League from ending with the heartbreak of relegation, Norwich City has sold out its allocation of just under 3,000 tickets for the clash at Craven Cottage.

That's on course to be biggest away following for a Premier League game this season - beating the 2,990 tally of fans who went to Tottenham.

The Carrow Road club has laid on seven coaches for fans travelling to the game, while supporters are also set to make the trip by train for a game which now has added spice, following the miserable 1-0 home defeat to West Brom last Saturday and the sacking of boss Chris Hughton.

The Canaries' board will be hoping that the appointment of fan favourite Neil Adams as manager will see the supporters get right behind the team in the Big Smoke, as they look to secure three crucial points against their fellow relegation strugglers.

And, with the final four games of a troubled season coming against the might of Liverpool, Manchester United, Chelsea and Arsenal, time is running out to pick up the points needed to avert a painful return to the Championship.

But Norwich's record against Fulham is not good. The Canaries last beat them in March 1986, when they emerged 2-1 victors at Carrow Road and have not won away since New Year's Day in 1986.

They were relegated from the Premier League at Craven Cottage on the last day of the 2004/05 season, when they lost 6-0 on a day when, as it turned out, a draw would have seen them stay up.

This season, Fulham knocked the Canaries out of the FA Cup at their place in a third round replay, while a late strike by former Norwich City loan player Scott Parker secured the Cottagers a 2-1 victory at Carrow Road on Boxing Day.

If the unthinkable happens, and Norwich City tumble out of the top flight, it is likely to mean an estimated £40m drop in income, such is the money Premier League clubs get thanks to television deals.

It will also have an impact on the city, with the feel-good factor of competing against the best clubs in the world replaced by games against the likes of Middlesbrough, Bolton and Watford. Not to mention Ipswich, so long as their play-off hopes are dashed.

Chris Starkie, managing director of New Anglia Local Enterprise Partnership, said: 'It's important for the city to have a Premier League club: it's important because of the money that it brings into the city, both in direct benefit to the football club and other businesses, pubs and hotels, but it's psychologically quite important too.'

There are other benefits – in delivering a feelgood factor boost to businesses and their customers, and acting as a powerful promotional tool for the region.

Mr Starkie added: 'Being in the Premier League can put a city or a region on the map. The Premier League is broadcast to well over a hundred countries worldwide and it's a huge opportunity to get the name of Norwich and the county of Norfolk out to a global audience. It's the kind of marketing that would cost millions in terms of free promotion.

'When you are trying to relate where you live to an international audience, it's important to have strong things to say. To be able to say 'we are Norwich, we are in the Premier League' brings easy and simple recognition.

'Football is a worldwide sport, that's pretty obvious, but the Premier League is a worldwide brand.'

Kevin Hopkins, landlord at the Ketts Tavern and a Norwich City season ticket-holder said: 'Unusually, Norwich City supporters are incredibly loyal and even when the club dropped to League One, 21,000 season ticket-holders and the ground being pretty full most weeks means that it doesn't in fact make a significant difference to the footfall of people coming in as they go to the game.

'What's made a difference to us is that ability to show the games on the telly and bring the crowds in to watch the games that they want to watch in that league – they are not available for us to show in the lower leagues, and that makes a significant impact on our business.'

He said days when Norwich City play, whether home or away, are the pub's biggest days of the week.

Mr Hopkins said: 'The plus side of it being a struggle is that people do want to watch the games and they will come out and watch them. What we are all hoping is that that struggle ends successfully, and not in relegation.'

• Turn to the sports pages for a full preview of today's crucial clash with Fulham.