An independent investigation into alleged bullying at Stobart Group has been completed.

The firm released its interim results to the London Stock Exchange and said "there is no culture of bullying within Stobart Group".

It appointed Alice Mayhew, a senior employment barrister at Devereux Chambers, to carry out the independent review into the concerns raised by some employees regarding alleged bullying and whistleblowing.

A statement said: "The investigation was completed on October 18 and concluded that there is no culture of bullying within Stobart Group.

"Interviewees did not report having been bullied or subjected to undue pressure or having witnessed bullying or undue pressure being placed on others.

"The report made recommendations, and the company is currently reviewing how best to incorporate these."

Shares in Stobart nosedived after the infrastructure group swung to a half-year loss.

The firm, which owns Southend Airport, posted a £17.5 million loss in the first six months of the year, compared with a profit of £111.9 million in 2017.

Stobart said the poor figures were due to investment in Southend Airport route development and marketing.

Shares tumbled more than seven per cent to 199p in morning trade.

But revenue grew 21.4 per cent to £151.3 million, boosted by the performance of aviation security.

The firm, which is planning to open Carlisle airport for commercial flights in the spring, said its aviation arm was accelerating passenger growth, with passengers at its London Southend terminal rising by 37 per cent.

Its energy business has seen a year-on-year improvement but its rails and civils arm saw a loss of £4.8m, although the group, in its statement to the London Stock Exchange, said the appointment of new commercial team strengthened management, with the division undertaking a detailed review of its commercial operations, contracts and project finances.

It added that it has strengthened its commercial management and governance.

Its board saw the appointments of Nick Dilworth as chief operating officer and Ginny Pulbrook as non-executive director and Michael Williamson was appointed interim chief financial officer.

Independent search firm, Russell Reynolds, was also appointed to identify additional board appointments.

Warwick Brady, chief executive, said: "We have remained focused on operational progress in our aviation and energy divisions, which have both performed well in the period.

"Having invested in the infrastructure for these divisions, we are now well placed to accelerate our commercial growth plans and demonstrate the value of the group's excellent operating businesses."