The landmark case of a UK-based Nepalese colonel accused of torture in his home country more than 10 years ago has collapsed amid fierce criticism.

Kumar Lama, 49, from St Leonards, had faced a retrial at the Old Bailey after a jury earlier this year cleared him of one charge of torture but could not decide on a second.

But at a hearing today, prosecutor Duncan Penny QC said the Crown had "carefully and thoroughly considered the evidence on the remaining count and considered there was no longer a realistic prospect of a conviction."

He said the Crown no longer sought a retrial and Mr Justice Sweeney formally acquitted Lama.

The decision not to go ahead with the retrial was made following inconsistencies in the evidence which the Crown was previously unaware of.

The case dated back to his time at an army barracks in Nepal in 2005 during the country's civil war in which more than 15,000 people were killed.

It was alleged that while acting as the commanding officer of an infantry battalion, he ordered the torture of two detainees held at the barracks.

He was arrested in January 2013 while on leave in the UK from his posting as a UN peacekeeper in South Sudan.

He was charged under section 134 of the Criminal Justice Act which allows suspects to face trial before a British court even if their alleged offences are committed abroad and they are not UK citizens.

The original trial last year had to be abandoned after it was blighted with problems over finding Nepalese interpreters. In all, the case is estimated to have cost the taxpayer around £1 million.

After Lama was cleared, his solicitor Jonathan Grimes, of Kingsley Napley, said: "I am extremely pleased for Colonel Lama that this case is finally at an end and that he can put these allegations behind him.

"The jury's verdict in August on one of the charges, and today's decision by the CPS on the other, confirm what Colonel Lama has always maintained: that he never ordered, or was complicit in, torture.

"The past three and a half years has been an extremely frustrating and stressful period for Colonel Lama and his family. There have been unacceptable delays in bringing this case to a conclusion, none of which have been any fault of his.

"He has borne these delays with great patience and good spirit and has always trusted that justice would prevail. I am pleased that Colonel Lama, an officer who has served with distinction with both the Nepalese Army and the UN, will now be able to return to Nepal and resume his military career."

He added: "I hope that the CPS will reflect carefully on its selection and management of this case and will learn lessons for the future."

A Crown Prosecution Service spokesman said: "This was an unusual and challenging case and we respect the decision of the jury. We will not be seeking a retrial having considered the developments at the trial."