I believe a recent easyJet press release descibed SEN as the first new airport to be built in the South-East for decades and I suppose that description isn't far from the truth when all the renewals/developments are taken into account. Virtually all the infrastructure is new with the exception of the original runway strip and that has been resurfaced with centreline lighting and a new drainage system etc. installed.
We could argue about the 'for decades' bit, but this sounds very similar to what happened to Stansted before it 're-opened' in '91?