A further four people have been arrested today in connection with a national investigation into high-value museum thefts which saw police swoop on addresses in Cambridgeshire as part of dawn raids across the UK.

A 30-year-old man and two 17-year-old boys were arrested in London, while a 37-year-old man was arrested in Hull.

All four are being held on suspicion of conspiracy to burgle.

The latest arrests come a week after 20 people were arrested following a series of early morning raids across England and Northern Ireland.

The 18 men and two women have since been bailed until January.

Officers from 26 police forces and the Serious Organised Crime Agency (SOCA) are involved in the investigation into six crimes over a four-month period at museums and auction houses across England.

Chinese artefacts and rhinoceros horn were targeted in six incidents - two thefts and an attempted theft from Durham University Oriental Museum and further incidents at Gorringes Auction House in East Sussex, Norwich Castle Museum in Norfolk and the Fitzwilliam Museum in Cambridge.

While much of the property has previously been recovered, several high-value items are still missing.

The Association of Chief Police Officers (ACPO) has set up a working group to crack down on the emerging issue of heritage crime. The group brings together police officers, English Heritage and other partners in the arts and museum sector to share intelligence and crime prevention advice.

Anyone with any information should call Crimestoppers, anonymously, on 0800 555111.