The McCartneys are vocal campaigners against the fur trade

The BBC One Real Story special had 1.8 million viewers from 2100-2200 BST, 7.6% of the available audience, according to overnight figures.

Arsenal's victory over Villarreal was watched by two million people on pay-TV channel Sky Sports 1.

ITV1 drama Murder City hit five million viewers in Wednesday's 2100 slot.

It was the most watched programme at that time, followed by BBC Two's The Apprentice.

Fur campaign

Sir Alan Sugar's search for a new employee had an average audience of 4.5 million, while Channel 4's Grand Designs attracted four million.

Only Five's Greatest TV Wind-Ups had a smaller audience than the McCartneys' documentary in the same timeslot, seen by one million viewers.

The Real Story team followed the McCartneys for six months as they campaigned against the use of fur in the fashion trade.

The couple were filmed taking their fight to the European Union to appeal for a ban on the trade in dog and cat fur.