Cherie Blair is having problems with a goat. "I'm going to call her She Who Must Be Obeyed, because she's certainly not obeying me," she says, as a grumpy brown Nubian with a lumpen head and an underbite wraps its lead around her legs and refuses to budge.
In fact, her new friend is male – a seven-year-old billy goat, named, er, Billy. He is one of 23 of the beasts being herded by celebrities across London Bridge to mark International Widows' Day, the UN's annual global day of action to address the poverty and injustice faced by millions of widows and their dependents across the world.
"I hadn't realised they were so strong," admits Mrs Blair. "I'm from Liverpool; we don't have any goats."
The procession has been organised by the Loomba Foundation, the widows' charity of which Mrs Blair is president. As freemen of the City of London, she and Lord Loomba are exercising their ancient right to herd livestock over the landmark bridge, which spans the Thames from Borough to Monument.
The halting procession makes its way towards Monument in a fenced-off bus lane. Only one a day after the chaos of a bus strike in the capital, Londoners, if they had been allowed to get near, might have been forgiven for thinking that the parade of farm yard animals was their replacement service. Fortunately, the public was kept at arm's length, on the other side of the bridge.
The Billy Goats Gruff have little to fear from trolls blocking their crossing, but someone is blocking the way at the end. A protester muscles in at the last minute carrying a banner saying "Spot the Irony: Blair Kills Husbands".
Bundled off before she is noticed by Mrs Blair, Rose Wynes-Devlin, 53, a mother of five from south London, says: "I'm a widow and I'm insulted that Cherie Blair is the president of a widows' charity. I lost my husband 13 years ago due to health reasons, but I know what it is for a child to grow up without a father, which is why I'm antiwar."
The bedraggled parade, completely soaked by the incessant rain, is to have been led by celebrities including Mrs Blair, Cilla Black, Nancy Dell'Olio and the television presenter Floella Benjamin. In reality it is led by their goats, who try valiantly to trip up their herders by weaving in between them on long leads.
Also at the front is Lord Raj Loomba, who set up the charity to help widows in memory of his mother, Shrimati Pushpa Wati Loomba, who was widowed at the age of 37 in India.
Commenting on the significance of the creatures, Mrs Blair says: "Goats are amazing for widows because you can use them for so many things. They can provide milk and an income to support your children."
These particular animals travelled down from Derbyshire and are far more interested in a bucket of barley than in the gathered dignitaries.
A six-year-old Toggenburg called Dotty is the star chosen to lead the procession. Floella Benjamin gives Dotty a tentative stroke, saying: "I like goats." Thankfully her reasons were delivered out of earshot of Dotty: "I'm from the Caribbean and there's nothing better than curried goat."
Miriam Gonzalez Durantez, the wife of the Deputy Prime Minister, Nick Clegg, had also been expected, but perhaps decided that goat herding in the pouring rain was not her thing. The Cleggs later hosted a reception for the charity at No 10.
As the procession makes it to a pen on the other side of the bridge, Billy picks up the pace and starts straining at the lead in Mrs Blair's hand. "I think the goats have decided they've had enough," she says, handing the lead to its owner with a look of considerable relief.