Police are hunting for skinny would-be thieves who cut their way into a bank, but were thwarted when the building filled with smoke.

Officers said the “audacious” attempt to break into the branch of Santander was by people who would have to be small and slim to fit through the hole they cut.

The incident took place at 4am on Sunday, when police were called to reports of people on the roof of the bank in Ash Lane, Rustington, near Littlehampton.

When they arrived they noticed that a hole had been cut in the roof and a number of people had entered the bank with an angle grinder and attempted to cut open a cash machine inside the branch.

The alarm was set off and security smoke was released inside the building. When members of the public disturbed the intruders by shouting at them the group fled from the bank empty-handed and got into two cars waiting nearby.

The cars drove off westbound along The Street. One of the vehicles was a white hatchback and the other was a dark hatchback. The thieves were wearing dark clothing and balaclavas.

Detective Sergeant Michelle Auger said: “This was an audacious attempt to steal from the bank that was thwarted by Santander’s defences and the members of the public who challenged the thieves.

“We need to speak to anyone who saw the raid taking place or the thieves escaping.

“We are particularly keen to speak to anyone who may have seen people acting suspiciously around the branch in the days or weeks beforehand or who saw the getaway vehicles.”

Witnesses to the incident should call Sussex Police on 101.