Patrick Boyle and his son Mark, who ran one of the biggest haulage firms in Northern Ireland – Boyle Transport Ltd – were caught following a complex operation by Cumbria police.

Officers stopped their vehicles as they travelled through Penrith and were able to work out the true nature of the journeys thanks to odometers found on the trailers, which the Boyles used to keep their own genuine records.

Both admitted falsifying tachograph records between November 2007 and October 2008.

Carlisle Crown Court heard how a priest and two politicians were among those who wrote in support of them.

Boyle senior, 65, and Boyle junior, 36, both initially denied the charges but changed their pleas after their drivers gave statements to the prosecution. They also resigned as directors of the company.

Yesterday, Carlisle Crown Court heard that an estimated 80 per cent of Boyle Transport journey’s involved falsification of records.

The firm is licensed in Northern Ireland but in effect operations are run from Scotland.

Prosecutor Jacob Dyer said one driver was on the road for 14 hours non-stop to Calais, then told to keep going until he hit Frankfurt.

Police uncovered a resignation email from one driver which stated: “I’m not prepared to risk my life, or other people’s lives or a jail cell for you to make profit.”

Defence barrister Richard Littler, on behalf of Patrick Boyle, said the fraud was aimed at keeping existing customers rather than obtaining new ones. Competition from European firms with lower operating costs was blamed.

Mr Littler showed the court with several letters of reference. The referees included Conor Murphy and Danny Kennedy - the Sinn Fein and Ulster Unionist Party representatives for the Northern Ireland Assembly constituency of Newry & Armagh.

A local priest, reverend and hospice manager were also among those paying tribute to the Boyles’ charitable work and good character.

In a separate defence of Boyle junior, barrister Hunter Gray said that his client had joined the family firm at just 16 and was therefore strongly influenced by his father.