Masked knife-wielding youths targeted a deserted petrol station in the hope of a bumper payout but came away empty-handed.

Two youngsters, thought to be aged 16, burst into the Esso garage in High Street, Royal Wootton Bassett at around 9.30pm on Saturday and threatened a cashier with a nine-inch blade.

The pair, wearing the same clothing as they wore in a similar raid in Swindon the night before, used the same tactics, with one holding the door open while the other waved the knife at the cashier.

But they left empty-handed when another member of staff pressed a security alarm.

Detective Constable Megan Kenzie, of Swindon CID, said: "At the time of the incident the staff member on duty states that two youths entered the shop, both with their hoods up and wearing bandanas over part of their faces.

"These incidents have left the cashiers shocked and somewhat distressed. They have been left with this lasting memory and are extremely concerned for their safety at work.

"I don’t know if they thought they were being clever and that there would be a large amount of money at the garage because of the panic-buying.

"Obviously they are targeting petrol stations thinking they are loaded with cash. But like betting shops, garages don’t keep all the money in the tills.

"This is now the second incident in a matter of days and the police need the assistance of the public to stop this from happening again.

"I would like to appeal for witnesses who can identify these males in the images or perhaps were in either area at the time the offences occurred and noticed these two persons acting suspiciously."

One of the men was wearing a grey hooded top, dark trousers and trainers and held the door open while his accomplice approached the cashier holding a knife and demanded he hand over the money from the till.

On Saturday they both made their escape into the neighbouring Poets Estate.

Both of the men are described as white and aged about 16. The men holding the knife was wearing a dark blue Adidas hooded top with lighter stripes, dark trousers and trainers.

Anyone with any information about the incident should call DC Kenzie on 101 or Crimestoppers anonymously on 0800 555 111.