A 68-year-old woman who was knocked to the ground in a post office raid has died from a blood clot.

A post-mortem examination yesterday revealed Margaret Hopkins, who was a customer in the sub-post office at Jengers Mead, Billingshurst, when an attempted robbery took place, developed a blood clot in her leg which later moved and killed her.

The examination was carried out at New East Surrey Hospital in Redhill by a Home Office Pathologist.

Mrs Hopkins was pushed to the ground as the man, who threatened staff with a knife and injured another customer, demanded money and then escaped empty-handed.

She suffered six broken ribs in the attack on October 17 at 10.30am and was treated in hospital but released the same day.

On Thursday this week, she collapsed and died at her home in West Street, Billingshurst.

Detective Chief Inspector Kevin Moore said: "The key issue now is how did Mrs Hopkins sustain those broken ribs? What was the exact sequence of events that led to her being on the ground?

"We still need to identify the offender. Clearly, what has happened has heightened the need to find him."

A man was arrested last week in connection with the attempted robbery. He was released without charge on police bail.

Anyone with information is asked to call Sussex Police on 0845 6070999 or call Crimestoppers on 0800 555111, quoting Operation Gambit.