LONDON-Braving the English summer, thousands gathered in the rain for a street party outside Buckingham Palace on Sunday, part of a weekend of celebrations to mark Queen Elizabeth II’s 90th birthday.

Some 10,000 people were expected to attend the open air Patron’s Lunch on The Mall in London, along with the monarch, her husband Prince Philip and Princes William and Harry, two of her grandchildren.

The guests will dine on sandwiches, snacks and puddings from British producers. Adults will even get a can of Pimm’s, a fruit punch popular at summer garden parties in Britain.

While The Mall was lined with giant British flags to create a ceremonial atmosphere, many of those gathering at the tables laid out along the way were forced to don plastic ponchos handed out by organisers to keep the rain off.

“Rain won’t spoil the party,” insisted one guest, Noreen Chisholm. “Everybody is so happy to stand in the rain to be part of the queen’s birthday.”

“The British spirit will come through the rain,” fellow guest Andy Moor told AFP.

Tickets for the event cost £150 (190 euros, $215) and most of the guests were from organisations with which the queen has links.

The BBC was televising the Patron’s Lunch which could also be watched via big screens set up in nearby St James’s Park and Green Park.

The not-for-profit event was organised by the queen’s grandson, Peter Phillips, the son of Princess Anne. “The queen has had many celebrations in her honour over the years but there’s never really been an appreciation or recognition of the number of organisations she is personally attached to through her patronage,” Phillips said.

The event will also feature a parade themed around the different eras of the queen’s reign, such as “flower power” for the 1960s. The widely respected monarch took the throne in 1952.

The lunch will bring to an end several days of celebrations to mark the queen’s official 90th birthday. These began on Friday with a special service at St Paul’s Cathedral in London.

On Saturday, the queen took the salute at the Trooping the Colour military parade which drew a crowd of thousands, with her vivid green outfit causing a sensation.

After Trooping the Colour, members of the royal family gathered on the balcony of Buckingham Palace to watch a military flypast, including Prince William and Kate, plus their young children George and Charlotte.

At least 1,000 smaller street parties are also expected to take place across Britain to mark the birthday.

The queen celebrates two birthdays as part of a royal tradition which dates back over 250 years.

The actual date of her birth is April 21, 1926. But her official birthday is also marked in Britain on a Saturday in June with Trooping the Colour. It is this event which has been expanded this year.