At midday dozens of protesters who'd been waiting quietly inside the store stood up, unfurled their banners and leaflets and began chanting: "Starbucks - pay your taxes! Starbucks sucks money from the UK! Boycott Starbucks - tell your friends!"

The cafe's manager appeared unsure how to react. At one point it looked as though he was going to lock everyone inside. A small group of police officers went in and after half an hour the protesters left - peacefully but noisily - to join another group at a second Starbucks nearby.

As far as UK Uncut are concerned, Starbucks' offer to pay £20m is a marketing stunt. Many passing Christmas shoppers we've spoken to seem to agree that the law needs to be changed to force multinationals to pay more tax in the UK.

Starbucks has paid £8.6m in corporation tax in its 14 years of trading in the UK, and nothing in the last three years. The company had UK sales of nearly £400m in 2011 but has reported a taxable profit only once in its 15 years of operating in the UK.

Starbucks now says it expects to pay around £10m in corporation tax for each of the next two years, a move described by tax experts as unprecedented.