An Irish man in his 50s, who was arrested by police in Wiltshire in England after 15 people were found in the back of his lorry, has been released from custody.

Sean Delaney International Transport, who owns the lorry, said the company's driver is now free to return home and is expected to return to Cork in the coming days.

The man was arrested following reports of "suspicious activity" involving his vehicle.

Wiltshire Police said they closed a road near Chippenham after being called by a member of the public shortly before 8.30pm yesterday.

The man was arrested on suspicion of assisting illegal entry. 

The man's employer said it was satisfied that neither it nor the company's driver had done anything wrong.

All of the people who were discovered in the lorry are believed to be between the ages of 16 and 30 and none is thought to be in a serious condition, according to police.

One person was taken to hospital for further checks. All 15 were arrested on suspicion of entering the UK illegally.

The UK Home Office, which assumed responsibility for the investigation, has said they presented as Iranian and Iraqi. .

Operations Manager Michael Delaney at Glanmire-based Sean Delaney International Transport told RTÉ News he knows everything from his company's side is "100%".

Mr Delaney said it was his driver who raised the alarm and alerted police.

He said both he and the driver are assisting police in the UK with their inquiries.

It comes after the discovery of the bodies of 39 migrants in a lorry in Essex last month.

British police have formally identified them, with police in Vietnam confirming that all 39 victims were Vietnamese.

Eight people were arrested in Vietnam earlier this week on suspicion of organising people smuggling overseas.

The 31 men and eight women who were discovered in the back of the refrigerated truck are thought to have been Vietnamese.

So far two people are facing charges as part of the investigation in Britain.

Essex Police have begun extradition proceedings to bring 22-year-old Eamonn Harrison from Ireland to the UK.

Under the European Arrest Warrant issued for the 22-year-old, from Mayobridge in Co Down, he faces 39 manslaughter charges, conspiracy to commit human trafficking and conspiracy to assist unlawful immigration.

The driver of the lorry, Mo Robinson, 25, appeared at Chelmsford Magistrates' Court charged with 39 counts of manslaughter, conspiracy to traffic people, conspiracy to assist unlawful immigration and money laundering.

Detectives have also urged Ronan Hughes, 40, and his 34-year-old brother Christopher, said to have links with the road haulage and shipping industries, to hand themselves in.

The pair, from Co Armagh, are wanted on suspicion of manslaughter and human trafficking.