The Civil Partnership Act came into action yesterday, heralding the UK's first gay weddings.

As hundreds of same sex couples line up to tie the knot in Brighton and Hove following the momentous change in law, canny wedding companies are hoping to exploit the power of the pink pound.

They have been in a loving and stable relationship together for 14 years.

But in the eyes of the law, Roger Lewis and Keith Willmott-Goodall only became a legitimate couple yesterday.

Sussex Police worker Roger, 57, and his partner Keith, 64, were one of the first same-sex couples to register their intention to form a civil partnership at Brighton Town Hall.

Although the act came into effect yesterday, Roger and Keith will have to wait until December 21 before they marry.

Under the law, rather like registering wedding banns, there has to be an official period of declaration. Roger and Keith and 18 other couples gave notice yesterday.

They were the first pair to sign-up when Brighton and Hove City Council started an unofficial pink weddings register last July in preparation for the change in law and were invited to be among the first three same sex couples to marry in the city, or indeed anywhere in the UK.

Roger said: "It has been an emotional rollercoaster for us and this morning made things seem very real and official. We spoke to the registrar, Linda Holme, and she asked us a number of questions, like were we free to marry, and we also gave her lots of biographical details.

"She spoke to us both individually and then together.

"We are delighted to be among the first three couples to marry.

"Keith and I have been together for 14 years and have waited a very long time to make our partnership legal. We want to demonstrate our commitment to one another and, of course, there are important legal aspects.

"Now we can officially be regarded as each other's next-of-kin, which is very important to same-sex couples, especially when they do not get on with their families.

"Previously, hospitals would not give out next-of-kin details to a same-sex partner. Luckily, in our cases, our families are very supportive and I have asked my sister Margaret to be a witness."

Roger and Keith will tie the knot at 8am at Brighton Town Hall on December 21, followed by a reception for 50 people at the Hilton Brighton Metropole.

With 198 ceremonies planned before the end of the year and 500 booked in total, Brighton and Hove will be the pink weddings capital of the UK.

The closest rival is Westminster, with a comparatively few 140 provisional bookings.

Gay couples have been getting "married" in blessings ceremonies for many years but they meant nothing in the eyes of the law and could not be sanctioned by registrars.

The Civil Partnership Act does not use the term "gay marriage" but the civil partnerships have been designed to be as close to a marriage contract as possible.

Partners will be extended the same property and inheritance rights as married couples and benefit from advantages in pensions, immigration and tax matters.

For the first time they, will have a right to benefit from a dead partner's pension, be able to succeed to tenancy rights and gain parental responsibility for a partner's children. They will even be able to dissolve the agreement in a form of divorce.

Gino Meriano, 42, had two reasons to celebrate yesterday.

In the morning, he registered his intention to wed Mike Ullett, 44, in Brighton on December 21. And as founder of the same-sex marriage organisers Pink Weddings, his business depends on the Civil Partnership Act.

Gino was coorganiser of a Gay Wedding Show at the Brighton Hilton Metropole on Sunday, which attracted 600 couples and 70 exhibiting businesses.

Specially-tailored services on show stretched from gay and lesbian cake toppers to legal and financial advice.

His and his towels, hers and hers bathrobes and chocolate fountains were in high demand.

There were also hoteliers, florists, solicitors, jewellers, harpists and cake decorators, along with registrars from Brighton and Hove and Cornwall issuing advice and answering questions about civil partnerships.

Representatives from major names like Debenhams, Moss Bros and Holiday Inn rubbed shoulders with drag queens and semi-naked butlers handing out truffles.

Guests were entertained by live artists throughout the day, including Four Poofs And A Piano, a Brighton band which stars on BBC1's Friday Night With Jonathan Ross.

Mr Meriano, of Weybridge, Surrey, said of the show: "There was a buzz like you would not believe.

Excitement, enjoyment, realisation of the fact that it was history in the making.

"Our aim with the Gay Wedding Show is to show equality and diversity.

"We don't have to talk about being gay, we just talk about getting married."

Same-sex weddings are set to become big business.

Asda's range of "Mr and Mr" and "Mrs and Mrs" cards will hit stores this week. And sets of "Darling, Dearest, Queerest" embroidered towels and soaps went on sale at Superdrug on Friday.

Co-organiser Ben Spence said: "My business Pink Products, which sells accessories such as cufflinks, pink passport covers, invitations and so on, has seen a 60 per cent increas in business in the past six to eight weeks.

"An entirely new industry has been unleashed thanks to the Civil Partnership Act and companies are waking up to that.

"We would never have seen high street names like Debenhams at the show last year.

"Now they will be specifically targeting the gay market, which is great news for the industry but also marks a giant leap forward in attitude and perception."

Brighton and Hove's three MPs last night hosted a reception at the House of Commons with the gay charity Pride to celebrate the arrival of the Civil Partnership laws.

Des Turner, David Lepper and Celia Barlow invited equalities minister Meg Munn as the guest of honour, along with the Reverend Debbie Gaston, of Brightwaves Metropolitan Community Church, Brighton.

She is due to marry her partner of 16 years, Elaine Cook, on December 21. Sue John, deputy leader of Brighton and Hove City Council, said: "It is an historic day. Brighton and Hove is the gay capital of the UK and we are very proud of that.

"The gay community has brought a wonderful tolerant, cosmopolitan feel to the city and their contribution to tourism and other entertainment industries is very significant."