We got several estimates last year and they were working on £1300 per sq m for a two-storey extension. These were 'cheap' builders and they said it was because of massive increases in the price of materials. However, these are coming down in price at the moment and it will also depend on the area of the country you are in.
Yes, it is a lot more than £1000 per sq m, although it will depend on where you live.
We got 10 quotes last year - we kept going back for more quotes, because we just couldn't believe how expensive it was! We did go ahead in the end though, and are nearly finished now and very pleased with it so far. We chose a builder who wasn't the cheapest, but had excellent references because getting someone reliable and with good quality work was the most important thing for us.
So far, builders doing extensions are still reasonably busy in our area (the South East) although anyone doing new builds has got nothing to do.
I was told about £1k per sm, the only quote I have had so far (from a recommended builder) was £15k+VAT for a 6sm extension (2 outside walls & roof, knocking through & making good, moving radiator and internal door).
We were told £1000 per square meter. A fixed price quote for our two storey extension of 45 sq metres in total was £40k.
Friend's DH is a builder and we discussed with him doing it in stages getting the shell done first. His quote for shell only came to £17.5k plus then the internal electrics, plumbing, stud walling, plastering etc, which I'm sure would have come in at much less than the other quote.