Have Geologists found Britain’s biggest impact event?

Geologists think they have discovered the biggest impact event, recorded in rocks ~1.2billion years old in the Northwest Highlands of Scotland near Ullapool:

http://news.bbc.co.uk/1/hi/sci/tech/7314329.stm

Does the UK have an impact crater?

The much lauded anouncement of the discovery of an impact crater in the North Sea has been contested by other geologists who argue a different origin:

http://news.bbc.co.uk/1/hi/sci/tech/6503543.stm

Did the Tunguska event leave a crater?

The 1908 Tunguska event is the largets extra-terrestrial “impact” event of modern times. Some geologists think they have found a crater which can be attrubuted to the event:

http://news.bbc.co.uk/1/hi/sci/tech/6239334.stm

More details about the event:

http://news.bbc.co.uk/1/hi/sci/tech/7470283.stm