by Ruth McDonald
BBC NI London correspondent
The time is 10am on a Sunday morning and an open-topped Routemaster bus waits outside the Dorchester Hotel on Park Lane in London.
Five minutes later and it is draped in Northern Ireland flags, scarves and banners, as a bunch of Northern Ireland supporters stand back to admire their handiwork.
Northern Ireland fans drove through London in a double decker bus
Neal Anderson of the London NI supporters club is particularly proud.
It is the first time that Northern Ireland supporters have taken part in London's St Patrick's parade - one of the biggest in the world.
The celebrations attract thousands of spectators who line the parade route and enjoy a free concert afterwards in Trafalgar Square.
London's festival gives the legendary New York parade a run for its money - and this year Neal and his fellow supporters are determined to make their mark.
"We started the London NI supporters club about four years ago," Neal said.
"This is the sixth St Patrick's Day parade and, previously, Northern Ireland hasn't been represented. So we thought we'd do something about it."
To a rousing chorus of 'We're not Brazil, we're Northern Ireland', the Routemaster pulled out of its stand on the dot of 1200 GMT and inched down Park Lane, past the cheering crowds.
Place of honour at the front of the top deck went to a well wrapped-up Lawrie Sanchez, the manager of the NI team, who was enjoying himself immensely.
"If 2,500 fans and certainly a lot of these people here are prepared to come to Lichenstein to support us, I'm quite prepared to come a few miles down the motorway and support them," he said over a rendition of 'Lawrie Sanchez's Green and White Army'.
"It's lovely to be here," said the MP for Vauxhall, Kate Hoey, with a big smile on her face.
She is one of the founder members of the London Northern Ireland supporters club.
Laughing in the London rain
"We've got a great manager and great supporters and we're here to show London that we exist.
"For years, Northern Ireland football and Northern Ireland supporters were ignored and we're not going to be ignored any more."
Halfway down the route, some of the fans staged an impromptu game of cricket while the parade stopped for a bit, but within minutes everyone was on the move again.
The Northern Ireland supporters were clearly going down well with the crowds - a trumpet had been produced on the upper deck and a full scale 'Glory, Glory Northern Ireland' rang out as the Routemaster took the corner into Regent Street at a sedate three miles an hour.
By the time Nelson's Column was sighted, the sun had well and truly gone in and the first drops of rain had arrived.
A few took shelter down below, but most stayed on above. And as the rain turned to hail and sleet, the fans just sang and waved at the crowds below - clearly hardened to the elements after many a cold night in Windsor Park.
"The reception we've gotten has been amazing," said a soaked but delighted Neal Anderson as the end of the parade route loomed into sight.
"It's been a mix of pleasure and people waving - and a few bemused looks as well - but it's all part of the fun".