Thousands of Royal Bank of Scotland workers were warned to stay away from their office for a second day on Tuesday, as the clear up operation began following a series of environmental protests.

A small number of activists remained on site on Tuesday morning, after setting up camp at RBS’s Gogarburn campus on Thursday.

At its peak, an estimated 500 protesters gathered ahead of a ‘day of action’ on Monday, which culminated in a tense stand off with riot police.

Activists, who said they were taking action to raise awareness of the bank’s alleged investment in fossil fuels, caused disruption across Edinburgh.

Twelve people were arrested on Monday following a series of small level actions, which saw three protesters close a bank branch by supergluing themselves into its doorway, five activists try to occupy the offices of an energy firm in Leith and seven people attach themselves to the RBS carpark gates, causing massive tailbacks at the Gyle.

Later, on the RBS campus site, protesters used a catapult to launch an oily substance towards the bank’s HQ and fired water balloons and silly string at police.

However, while skirmishes remained at a low level, Lothian and Borders Police revealed that officers also seized a number of dangerous weapons from campaigners, including mesh hammers and a coal chisel.

They also accused protesters of putting lives at risk, after the poured what is believed to have been vegetable oil or diesel onto two busy dual carriageways.

Edinburgh City Council had to use more than seven tonnes of grit to clean the A720 at Bankhead and the west bound A8, while Lothian Buses removed its vehicles from the roads for a spell.

A police spokesman said: "This was an extremely reckless and dangerous act which could have put many members of the public at risk.”

Protestors were arrested after they took action in the city's Nicolson Street, as well as at Forth Ports, Gogarburn Bridge, Hunter Square and Glasgow Road.

At Nicolson Street, a 25-year-old man and two women, aged 38 and 34, were arrested and charged with breach of the peace.

Two men, aged 20 and 49, and three women, aged 23, 41 and 18, were arrested and charged with breach of the peace following an incident at Forth Ports.

A 58-year-old man was arrested and charged with assault in relation to an incident on Gogarburn Bridge, while a 24-year-old woman was arrested and charged with vandalism in the city's Hunter Square.

A further two men, aged 31 and 33, were charged with breach of the peace in relation to an incident in Glasgow Road, Edinburgh.

Most of those arrested are expected to be released on an undertaking to appear at court at a later date.

A spokesperson for Lothian and Borders Police said: "While the Force facilitates peaceful protest, public disorder, damage to property, or any other criminal acts will not be tolerated.

"It is obvious that the activists changed their emphasis, and we had considerable resources in place to respond in a proportionate and responsible manner.

"A significant amount of planning had been put in place for the Climate Camp so that the Force was prepared for every eventuality, and additional resources were sent to the RBS site to support the policing operation there.”

Police said that, despite the stand off, there was no significant damage caused to the RBS HQ building on Monday, however, two women were arrested after smashing a number of windows and causing significant damage on Sunday night.

On Tuesday, the bank confirmed that the majority of staff would stay away from Gogarburn again, but said contingencies were in place to allow them to work from home or from other offices.

An RBS spokesman said: "Our main concern has been the safety of our workers so we have only minimum staffing levels in place at Gogarburn today. The children's nursery is closed for the same reason.

“The impact of this on our customers and operations is negligible to nil as we have a full contingency plan in place."