An Australian family fighting deportation from the UK have accused the Home Office of "a rather extraordinary breach of trust" by changing immigration rules after they were granted entry to the UK.

Members of the Home Affairs Select Committee heard from Kathryn and Gregg Brain, who moved to Dingwall in the Scottish Highlands with their son Lachlan, now seven, in 2011.

The family's campaign to remain in the country following the withdrawal of the post-study work visa has made headlines around the world.

Mr Brain and his son came to Scotland as dependants of Mrs Brain, who was on a student visa at a time when a two-year post-study visa was in existence - but it was later abolished.

Glasgow Times:

They hoped a job offer made to Mrs Brain by GlenWyvis distillery in Dingwall would meet visa requirements and allow them to stay.

The announcement of the discontinuation of the post-study work visa scheme came in March 2011, just three months before the Brain family arrived in Scotland.

A day before they were due to be deported on May 31 this year, Immigration Minister James Brokenshire gave the Brain family leave to remain in the country until August, but they are not allowed to work.

READ MORE: Deportation-threatened Brain family to give evidence to Home Affairs Select Committee

Gregg Brain said the family had applied and been accepted for the scheme in 2010, and did not become aware of the changes to the rules until 2012 when the issue came up in the press, shortly before they came into effect.

He said: "With my knowledge of fundamental legislative principles from my Australian public service experience I was very quick to reassure my wife that it would not apply to us, that it would not be applied retroactively.

"As a matter of natural justice it must surely only be being applied to people who arrive after the date of the discontinuation."

Kathryn Brain, who was studying on the visa, was faced with finding a job which meets tougher Tier Two visa requirements, with a minimum salary threshold of £20,800.

She has been offered a job at a distillery which would meet the requirements, and is awaiting the applications being processed.

She said: "We just hope it all comes through by August 1 which is our deadline."

Mr Brain added: "This has by necessity been a seven-year exercise in the planning and the execution.

"They (the Home Office) had to envisage that people would have to plan this far ahead to be able to successfully execute the programme that they provided.

READ MORE: Deportation-threatened Brain family to give evidence to Home Affairs Select Committee

"That is why I felt it was a rather extraordinary breach of trust when we had a letter from Mr Brokenshire which said... 'applicants should never assume that provisions that are in place at the time of their entry to the UK will continue to be viable options in future years'."

Mr Brokenshire later gave evidence to MPs on the UK's immigration plans following the vote to leave the European Union.

Conservative MP Tim Loughton, chairing the committee, urged Mr Brokenshire to read the transcript of the Brain's evidence, saying the family have become "something of a cause-celebre".