FF Sheriff is similar, especially in the treatment of the lower case serifs:

http://www.fontshop.com/index.cfm?fuseaction=catalog.fontdetail&displayfontid=FF.10466.5.17&attributes.sampleSize=48&sampleText=BIG+Winner&sampleSize=48

Which? Magazine (which is the same as your sample I believe) uses is a custom-designed font family simply called Which. There is a serif (like the sample ) and a sans in a variety of weights. I don't know who designed it.

Marc's suggestion of FF Sheriff is an excellent one since the lowercase looks nearly identical. I wouldn't be surprised if it was the same designer.

Here are samples:

I did it for Which? magazine, so only they can use it. Sorry!

I didn't do FF Sheriff.

PS. James - how did you get these samples. Looks like somebody has been manual kerning on the serif; a bit tight between m and o.