Lesbian and Gay Pride, the annual celebratory march and festival taking place on Saturday, looks likely to return a sizeable profit for the first time.

The Pride Trust, the festival's organisers, have struck deals with several major sponsors whose support will guarantee the event's future and could fund new ventures.

The main income is from brewers Charrington, who have bought the festival's beer concession for a six figure sum and will contribute a commission to the trust on drinks sold. Seven festival beer tents will represent the brewery's gay pubs in London, such as Comptons in Soho and The Black Cap in Camden.

Additional sponsorship, worth more than pounds 30,000, has come from organisations including the public service union Unison, the Ministry of Sound nightclub and Gay Times. With sponsorship income of about pounds 250,000, the organisers are confident of greater financial security this year.

Profits will be ploughed back into organising next year's event, although they hope to use some money for activities beyond the annual summer and smaller winter rallies. One possibility is a London-wide cultural festival in the spring or early summer.

The Pride festival has become more commercial since 1992 when, despite making a small profit, a backlog of debts saw the organisation fall into receivership. The Pride Trust was subsequently formed to manage the event and sought outside funding.

The involvement by Charrington has been viewed with scepticism by some in the gay community who accuse the brewery of cashing in on the 'pink pound. In previous years the beer tents were run by gay bars and pubs who organised their own supplies and temporarily relocated at the festival for the day.

Adam Jeanes, chair of the Pride Trust, said there is no danger of the event being diluted by commercial interests. 'If a sponsor comes to us and wants to be associated with us they won't want to change the character of Pride. A lot of the organisations this year are gay positive or gay-owned; Charringtons is the biggest owner of lesbian and gay bars in the capital. There are some organisations we would say no to.

Saturday's festival will have a more overtly political tone than in some previous years, partly as it will mark the 25th anniversary this month of New York's Stonewall Riots, generally regarded as the start of the international lesbian and gay liberation movement. During three days of fighting, patrons of the Stonewall Bar in Greenwich Village clashed with police officers in protest at being persistently harassed.

The higher political profile follows criticism that last year's march was not a central part of the day. The Trust invited gay groups, such as Stonewall and OutRage, to suggest what form the festival should take, and it was agreed that the event should have an overall theme: '25 years out and proud, equality and freedom now]

Mr Jeanes says the slogan was chosen as one that the many strands of the gay community could all support. Within the march people will have the choice of supporting other causes such as lesbian visibility, employment rights and censorship laws.

The dominant issue, however, is likely to be the lowering of the age of consent for gay men to 18 which provoked widespread anger among gays and lesbians.

Stonewall is planning a demonstration by about 200 gay men under 18 who face prosecution for having same-sex relationships.

On Saturday the march will begin with a minute's silence in memory of people who have died of AIDS. About 50,000 people, including regional and international delegations, are expected to march from Hyde Park to Great Smith Street, near Westminster Abbey, via Park Lane, Piccadilly, Trafalgar Square and Whitehall. With good weather, that number is expected to double for the festival in Brockwell Park.

Mr Jeanes said he is delighted that after months of negotiating, the Metropolitan Police agreed that Pride could have the high-profile march route through central London that they had sought.

He is hoping that the success can be capitalised on by holding next year's Pride rally in Hyde Park rather than Brockwell Park, several miles from the end of the march. 'We had always been told that Hyde Park would be too small for us, but we learned it had been booked for D-Day events which would have attracted about 500,000 people.

'We were quite amused to find that out, and are looking into it. It would cost us a lot of money to have Pride in Hyde Park, but it would be wonderful.