This holiday weekend, I'm cooking for friends, wearing a Camilla mask, and decorating a jubilee cake. There will be a ping-pong tournament, drinking, and a trip to the cricket pitch to watch the village Olympics. Street parties, big lunches and barbecues are what most of us enjoy on these occasions. Of course the telly will be left on in the background so we can sneak a peek at the pageants and concerts and sneer at the outfits worn by lesser members of the Royal Family. My point is, this is sustainable tourism – most of us will not be straying far from home. Most tourism, though, is really bad for Britain. Do we need millions of foreign visitors arriving on our shores, dropping their litter, clogging up our public transport systems, getting into our museums gratis and creating traffic gridlock with their ugly coaches?

This weekend is just a rehearsal for what lies ahead. Come the Olympics, London will be in lockdown as thousands of visitors stream in – although high prices have deterred many and Thomas Cook is discounting its expensive corporate breaks to as little as £99. Helicopters will fly overhead day and night, with trained marksmen on board. There will be a heavy police presence and armed officers at key points around the site. The high-speed train service to the stadium will be so overcrowded, rail bosses are already telling workers they should plan to use other routes. Hour-long queues are anticipated for the six-minute journey. Residents will find it almost impossible to get around – and civil servants have been urged to stay at home. Most Londoners I know are getting out – hardly tourism, but forced relocation.

Living in central London for part of the week, I experience at first hand the downside of tourism. Pavements clogged with crocodiles of foreign school kids tramping around the West End, taking in nothing at all. Coaches showing visitors the "sights" in a single day. Life for Londoners during the peak season is intolerable. All around the world, mass tourism to prime destinations is ruining historic streets and urban environments. Siena and Florence are no-go areas from May to September. Venice is overflowing with tourists filming their entire trip, never once looking at anything. You can't walk six feet without encountering someone eating from a large plastic container while stumbling around clutching a guidebook, wearing repellent tight-fitting shorts, with a T-shirt straining at their belly.

Can anyone justify this kind of tourism? There's so much to be said for exploring places closer to home, ignoring the obvious, and the five-star sights. Countries and villages that welcome strangers on a small scale, where your money goes directly into the pockets of the local people, and not international chains.

When I read that the United Nations has appointed Robert Mugabe a "leader for tourism", it made perfect sense. The man who's reduced his own country to devastating poverty, who has spirited vast wealth abroad, who imprisons anyone he fancies – including a recent visitor from the UK, who was daring to work for nothing at a music festival for schoolchildren – BBC Radio 3 presenter Petroc Trelawny. Perhaps we should ship our unwanted tourists off to Zimbabwe.

Soft-shell crab burgers all round

My local petrol station at King's Cross has been turned into an elegant pop-up restaurant by the two chaps behind trendy Bistrotheque, David Waddington and Pablo Flack. Nowadays, pop-up restaurants are all the rage, but these two really pioneered the trend when they set up The Reindeer over Christmas in 2006, in a multi-storey car park off Brick Lane. The Filling Station is a chic wrapping of corrugated glass, that turns this windswept corner off York Way into a painting by Ed Ruscha.

Designed by Carmody Groarke, responsible for the 7/7 memorial and the new Bauhaus exhibition at the Barbican, the minimalist glazed structure envelopes the original kiosk. Behind the screen, the space backs on to the Regent's Canal – great for summer drinks and snacks. The diner is surprisingly small, and reminded me of bars I loved in Florida 30 years ago. The eatery is called Shrimpy's and the signature dish is a fearsome-looking delicious soft-shell crab burger.

Gay marriage row rumbles on

With just two weeks remaining for the public consultation on gay marriage, the battle is hotting up. The Archbishop of Westminster Vincent Nichols, the head of the Roman Catholic church in England and Wales, says it would have "damaging consequences", while leading rabbi Jonathan Romain can't see any problem.

The Out4Marriage campaign has been endorsed by MPs of all parties, from Jack Straw and Theresa May to Ed Balls, but Nick Clegg is furious that David Cameron is offering MPs a free vote. As I wrote in these pages, it's ridiculous to deny gay people the right to marry – we heterosexuals have made such a mess of it, maybe the gays can do better.

Tune in to me grilling Vince

Tune in to Woman's Hour on BBC Radio 4 tomorrow and hear me take on Vince Cable over the Governments' pathetic decision to scrap plans compelling companies to appoint a quota of female executives.

David Cameron has always said he was broadly in favour (describing women as an under-used asset), and European Union Justice Commissioner Viviane Reding says she would like to implement a quota of 30 per cent by 2015 and 40 per cent by 2020. Vince has obviously been nobbled by the M people in the City – Male, Middle-class and in Management – and now says the Government will not be introducing quotas, just encouraging a "change in culture". What an insult.

Although some boards have appointed more women in the last year, more than half of the FTSE 250 companies have no women on their boards at all. I asked Vince whether, if he were prime minister, he would follow the lead set by new French President François Hollande and make his cabinet 50 per cent female? Before the election, Cameron said a third would be female - another U-turn. Cable's reply is very revealing.

'Billy' is brilliant, seven years on

Billy Elliot The Musical, has just celebrated seven years and 3,000 performances at the Victoria Palace Theatre in London.

Written by Lee Hall, with music by Elton John and directed by Stephen Daldry, the show has been feted on Broadway, and productions are opening worldwide. It seems so long ago that I went with Elton to see Daldry's original film in a little cinema at the Cannes film festival. He related instantly to the story of a boy struggling to achieve his dream of dancing against massive opposition – in fact he sobbed from start to finish.

At last week's gala, Billy was performed brilliantly by 13-year-old Harris Beattie from Scotland – what a wealth of talent this show has produced – and a huge number of previous Billys were there to cheer him on. The story is set against the miners' strike of 1984-85, and seems even more apposite now, in the current recession.