Two masked and armed robbers who forced their way into a Frome store, tied up a female shop assistant and stole more than £5,000 have been sent to jail for four years.

Mark Yexley, 37, and Aeron Astley, 29, were waiting wearing black balaclavas and gloves, as shop assistant Shirley Inman prepared the Co-op store at Culverhill for opening at 5.20am on June 5, Taunton Crown Court was told.

She tried to stop them entering but failed and Yexley, who was carrying a knife with a seven-inch blade, said: "Don't muck me about, where's the safe? Don't mess me about or I'll knife you", and pushed her, said William Hunter, prosecuting.

He grabbed keys in the kitchen, told her to lie on the floor, taped her hands behind her back and emptied the contents of the tills into a holdall they had brought with them.

The shop assistant was then taped to a chair and Yexley went over to the security camera, which was not switched on, and they left.

Miss Inman, who was still tied to the chair, tried to make her way to the shop door but a regular customer, who lives opposite, had already called the police and the men were arrested near the car they had arrived in.

Yexley later said the robbery was committed out of sheer desperation because he needed money for his little girl who lives in Thailand. He had watched the shop for a few weeks so he knew a solitary woman would be working there.

Astley said he was out of work and desperate for money.

"It was a pre-planned robbery on a shop where they knew there was only going to be one person, and they went equipped", said Mr Hunter.

He added that Miss Inman suffered flashbacks as a result of the incident.

Ben Tabiner, representing Astley, said his client had never been in trouble before and had "huge regrets".

Mr Tabiner said Astley was a qualified carpenter but had lost his job and his partner had ended their relationship, partly due to him not bringing home any money, and part-time work as a doorman did not provide enough for his son.

Emma Martin, for Yexley, who had 15 previous offences, said he felt remorse "for this poor lady who was caught up in his behaviour" and had meant her no harm.

He was caught up in total desperation for his six-year-old daughter who has been seriously ill since birth. He had been sending out increasingly large amounts and borrowing from family, friends and loan sharks.

In 2009 she developed a fever which resulted in a long hospital stay and he was told she would be discharged after three weeks because there was not enough money.

He burgled a recreation club and stole £4,000 to ensure she was not discharged from hospital to die.

His ex-wife's mental health deteriorated and he was very conscious that, as a practising Buddhist, she had no fear of death for herself or for her daughter.

"He thought his daughter would be killed if he did not send the money", added Ms Martin.

"He is a mild-mannered family man, proud and hard working, and behaved in a quite extreme way. He's deeply ashamed of his behaviour".

Judge Graham Hume Jones said the two men had targeted a small shop knowing there was only one female shop assistant, who was particularly vulnerable.

"You armed yourselves and tied the shop assistant up with tape, which must have been a terrifying experience", he added.

Both men both of Amesbury, Wiltshire were jailed for four years after admitting robbery and possessing an offensive weapon. Yexley was also given an additional 52 weeks in prison for breach of a suspended sentence.