A huge number of unsold lots in the British Postal Museum & Archive auction at Sotheby's left plans for a new museum in jeopardy.

The total realisation was a disappointing £400,920 (including buyer’s premium), for a sale with estimates of £5 million in total. Only 29 of the 191 lots sold.

The top realisation was £192,000 (including 20% buyers’ premium) for the 1918-19 Bradbury Wilkinson 2s 6d, 5s and 10s registration blocks of 36.

Another lot of the George V registration blocks was sold to a phone bidder, but other than that, the story of the sale was that only smaller pieces sold. There was interest at 50%-60% of the lower estimate for bigger items, but those bids failed to reach the reserve.

Many dealers were unhappy that the sale went ahead, and the Philatelic Traders Society had contacted the museum with their concerns.

They included that the material 'in some people’s opinion was mis-described', using catalogue values which were based on items from previous National Postal Museum sales in 1984-85.

At the time of these sales it had been stated that there would not be a release of any more archive material, and dealers felt this was a reversal. In a written response to these concerns, the museum stated: 'Although it inherited a number of National Postal Museum records, and was donated the material formerly in the National Postal museum’s custody, it is a wholly separate organisation. As such, it is governed by different rules, namely those for charitable organisations.'

Dealers also wanted the material to be handstamped as proof of authenticity. In the 1980s, material was stolen from the postal archive and sold by a curator, and it was feared that releasing similar un-handstamped material would legitimise this material.

There were also concerns that the registration blocks offered for sale were too big. One collector, who had picked up positional pieces for his own collection, said: 'There just aren’t any collectors out there with really deep pockets any more, not since "Chartwell" [Sir Humphrey Cripps] died'. He added that collectors required specific pieces to form part of an exhibit. 'It has to be positional, or a cylinder block. It has to say something.'

Another eminent collector criticised Stanley Gibbons catalogue values. The lower estimate was generally around 20% of the Gibbons value, and bids tended to stop at around 10%. 'It shows how ridiculous they really are.'

The BPMA declined to comment during the post-sale period when offers for unsold material could still be received by the auction house.

Commenting on the result, a Sotheby's spokesperson said: 'The sale was presented to the widest possible audience and with appropriate estimates, but the British stamp market did not support this historic opportunity to purchase rare and important stamps.'