A pensioner who sent death threats to Theresa May has been jailed.

Isabella Jackson, who previously served a two-year jail term for threatening to blow up a plane carrying President Barack Obama, admitted a series of charges at Kirkcaldy Sheriff Court.

The 73-year-old made the threats to the then-home secretary just months after she was released from her previous sentence.

A sheriff told her that her "twisted mind" had caused her to "cause the utmost disruption from the comfort of her sofa".

On November 24, 2014, Jackson sent an e-mail from her home in Buckhaven to aides of May in which she threatened to kill the politician.

On January 4 this year, the accused made bomb threats against Edinburgh Airport and Harrods and King's Cross Station in London.

She sent an email from her home in Buckhaven to the Police Scotland Professional Standards Department in Aberdeen and to the Professional Standards Department of the Metropolitan Police in the Empress State Building, Lillie Road, London.

The court heard she "sent information with the intent of inducing in them a false belief that a bomb or other thing likely to explode or ignite" was present at the retailer as well as at the two transport hubs.

Shortly after the bomb threats Jackson sent a package by post to the Levenmouth CID office in Methil, Fife.

In it she sent a packet of white powder and a card with the word "death" written on it.

Sheriff Grant McCulloch said he was satisfied her behaviour merited a further custodial sentence and jailed her for three years and nine months.

He said: "You've accepted your guilt for four offences, each of which is significant and caused major inconvenience, fear and alarm.

"You are no stranger to such behaviour. It is a deliberate act of a twisted mind, quite content to cause the utmost disruption from the comfort of your own sofa."

A further hearing will be held later on an application by the Crown for a serious crime prevention order that would curtail Jackson's internet use once she is released and subject her to police monitoring.