A mystery aristocrat was horrified to find out the garden ornaments bought by his family and dumped at the bottom of his garden were actually priceless, stolen 7th century artefacts after being confronted by a world-famous art detective.

Dutch art detective Arthur Brand tracked down the carvings which were stolen in 2004 from the Santa Maria de Lara church in northern Spain, and believed to be at least 1,000 years old.

The church from which they were stolen is believed to date from the era of the Visigoths, with experts dating it between the seventh and eleventh centuries.

They were covered in leaves and forgotten about at the bottom of a North London garden.

The identity of the aristocrat is unknown, and Mr Brand told The Telegraph the people who accidentally purchased the stolen art are so embarrassed that he has been sworn to secrecy about who they are.

He has been hunting the art for nine years, after receiving word from an unnamed British informant that "something strange" had popped up in London.

A French dealer had been seen arriving with the reliefs by truck in London, and were put on sale as garden ornaments for around £50,000 each. However, an eagle-eyed informant thought they were possible Visigoth religious artworks.