The two security guards, who were loading cash tills, were pushed to the ground in the attack in Marlowes at about 8.20pm last night (Thursday).

One of the guards was then punched in the face and sustained a black eye before the raiders fled with cash.

The two suspects were last seen running down an alleyway between Primark and a '99p shop'.

Police said there have been no reports of any weapons being seen during the robbery.

The raid follows a more serious robbery in Tring on September 16 when a security guard and a memeber of the public were shot by two armed cash thieves.

The first offender in yesterday's crime is described as black or mixed race, about 6ft 1ins tall and well built.

He had a deep voice and was wearing a dark coloured top with a hood up and a scarf covering part of his face.

The other man is thought to be of mixed race and had lighter skin than his accomplice.

He was described as being around 5ft 10ins tall and well built.

He was also wearing a dark coloured 'hoodie' and had a scarf covering his face.

Anyone with any information is asked to call Hertfordshire Police immediately on 0845 33 00 222 or Crimestoppers anonymously on 0800 555 111.

You do not need to give your name and you may be entitled to a cash reward.