Eli Frankham, 40, began the threats when his three children were excluded from a school football tournament because of "unacceptable behaviour".

Rachel Voss, head of the Anthony Curton School in Walpole St Peter, Norfolk, said the experience affected her professional and personal life.

At King's Lynn Magistrates' Court, Frankham was given an 18-week sentence.

Both he and his wife Vanessa admitted harassing Mrs Voss and being abusive towards members of her staff when they appeared before magistrates last month.

Vanessa Frankham, 39, was given a 180-hour community punishment order and a three-year Anti-Social Behaviour Order.

Police escort

Prosecutor Gwen Wallace told magistrates the incident stemmed from a disagreement over the behaviour of the Frankhams' three children, who had been excluded from a football tournament.

Mrs Voss was repeatedly intimidated after the children were suspended from school in March.

Frankham allegedly threatened to "do her", she said.

On one occasion she needed a police escort home from work, and also received at least eight phone calls from the couple.

Mrs Wallace said the campaign of harassment had left Mrs Voss feeling "like her life was unravelling".

School grounds ban

At the previous hearing, Mrs Voss described the couple's actions as "horrible", but said she had "emerged from this awful experience with the most enormous sense of gratitude and respect for all those people who have supported me".

Defence solicitor Paul Croker offered no mitigation on behalf of Eli Frankham, of Wisbech Road, Walpole St Andrew.

He was jailed for 12 weeks for harassment and given a further six weeks on a charge of intimidation - to run consecutively.

He will also be made the subject of a five-year Anti-Social Behaviour Order banning him from entering school grounds or intimidating those involved in the case.