What do Blackburn, South Shields, and Richmond (Yorks) have in common?

They are the only constituencies in the last 40 years to have had successive MPs serve in the Cabinet (whilst being their MP).

With around about the same number of MPs having served in government over that 40 years as there have been MP in any one parliament (around about the 650 mark) you'd expect on average each constituency to have had one government member.

But that's not the way it appears to have worked, even when you take out those seats never likely to have their MPs in government (Northern Ireland, the Scottish and Welsh nationalist strongholds, the Lib (Dem) seats (though only about a dozen could be said to be perennial seats for these three parties combined).

Barbara Castle and Jack Straw in Blackburn have clocked up 16 years in the Cabinet, over the last 41 years. Leon Brittain and William Hague in Richmond a more modest 8 years and David Clarke (remember him? - Cabinet minister in the Cabinet Office for a year, sacked by Blair at the first opportunity, responsible for the Freedom of Information white paper which ultimately, via many twists, led us to where we are today on MP expenses) and David Miliband in South Shields just 5 years.

Stockport appears to be the opposite of these seats, with none of their MPs over the last few decades having had a government post, though the incumbent Anne Coffey is one of the longest serving (perhaps the longest serving) Parliamentary Private Secretary for, firstly Tony Blair and then Alistair Darling