One of Scotland's richest women breached planning rules after she allowed an oak tree to be chopped down during building work in the grounds of her castle.

Ann Gloag, who shares a fortune estimated at around £1.04 billion with her brother and fellow Stagecoach bus company co-founder Sir Brian Souter, had been given planning permission to put up a new home in the grounds of Kinfauns Castle in Perthshire.

Workmen tore down an tree - which they had been advised was rotting - while starting construction on the three-bedroom property intended for use by a relative.

However, the planning permission from Perth and Kinross Council contained a condition that no trees were disturbed. An inspector noticed the felled tree after the businesswoman asked for planning permission to make the new property larger than originally planned.

The 72-year-old has now been told she will have to plant a replacement tree before the new house can be occupied.

In a written report, council planning officers said: "The previous application was approved with a condition requiring that remaining trees on the site be retained and protected.

"The Development Monitoring Officer, on visiting the site, identified that this condition had been breached.

"It was discussed that with this application being submitted the breach could be resolved through the inclusion of a condition requiring a replacement heavy standard oak tree to be agreed 'within three months of decision' and implemented prior to occupation of the dwelling house."

Mrs Gloag has made a number of applications to build new homes on land she owns near to the castle in recent years.

In 2012 she won a battle to erect two homes, including a six-bedroom mansion, despite protests from neighbours and conservationists.

Plans for the larger bespoke house attracted a strong objection from Forestry Commission Scotland, which warned it would ruin an area of ancient woodland.

Local residents claimed the houses would spoil the privacy and seclusion they currently enjoy and hit property prices.

Last year Mrs Gloag applied for permission for a row of three terrace houses on the site of a steading close to the castle.

However, the council ruled that the location of the proposed homes was part of a green belt site in an area of great landscape value that should not be built on.

Mrs Gloag won the right to restrict access to her property in 2007.

The case allows her to keep the public out of 10 acres of grounds.

Last year it emerged elderly couple Jimmy Bryan and his wife Lille faced eviction from had occupied for more than 40 years on Ms Gloag's Beaufort Estate, near Beauly, Inverness-shire.

The businesswoman's spokeswoman said that they were effectively given almost a year's notice to leave.

Mrs Gloag, who was awarded an OBE for her charity work in 2004, remains a non-executive director of Stagecoach, which started in 1980.

Her spokesman said: "The tree was removed on the advice of tree surgeons because it was rotting and it will be replaced."