If you think the job of the Metropolitan Police will be difficult this week as thousands of protesters descend upon the capital, spare a thought for Sarah Brown who has the unenviable task of entertaining the wives – and one husband – of the world's most powerful leaders.
The Prime Minister's wife is planning to host a "First Wives' Club" in line with conference tradition which dictates that spouses educate themselves, drink tea and raise money for their favourite charitable causes while their partners deal with the big issues.
Clearly the most important person on Mrs Brown's guest list will be Michelle Obama, the "First Lady of First Ladies". Mrs O has already scored a diplomatic triumph by securing a personal meeting with the Queen. On Wednesday afternoon – so long as the anarchists haven't forced the Royal Family into hiding – the world's most powerful couple will meet Prince Charles and Camilla before taking tea with Her Majesty at Buckingham Palace. Everyone else will have to content themselves with a brief handshake at an official reception.
The stringent security arrangements insisted upon by Mr Obama's Secret Service bodyguards also appear to be playing havoc with Mrs Brown's carefully laid-out schedule.
Downing Street is closely guarding the precise itinerary for security reasons but plans to entertain the First Wives' Club on the royal train apparently had to be abandoned because the Obama security team didn't approve.
A slap-up dinner on Wednesday night at Jamie Oliver's restaurant Fifteen was moved to Downing Street for the same reason. The chef will have to surrender his mobile phone – on the day his wife, Jools, is expected to give birth to their third child. Downing Street officials have been asked to keep him informed if she goes into labour.
In addition to fine dining, there will, no doubt, be plenty of "handbag summit" photo opportunities while Mrs Brown's charity, the White Ribbon Alliance for Safe Motherhood, is likely to feature prominently on Thursday, the day of the conference.
During last year's G8 in Japan, the first ladies were treated to a distinctly educational itinerary. First there was a visit to a "traditional village", then there was a traditional tea ceremony followed by a demonstration in the art of kimono folding.
Only two of the G20 leaders are women and as expected Angela Merkel's notoriously shy quantum chemist husband, Professor Joachim Sauer, will not be accompanying her. That leaves Nestor Kirchner, the husband of Argentina's President, Cristina Kirchner, (and himself a former president), the only male guest.
At least Mrs Brown won't have to worry about being upstaged by Carla Bruni-Sarkozy, who on her first official visit to Britain a year ago left politicians and press (mostly men of a certain age, it ought to be said) picking their jaws off the floor thanks to a series of astonishing outfits. Nicolas Sarkozy's wife will not be accompanying her husband to the G20. Nor will the four wives of Saudi Arabia's King Abdullah bin Abdul Aziz Al Saud make the journey.