On what basis?
The original St Lukes and Buro Hapold was 60,000.
There's a lot of conjecture saying it can't be this it can't be that, ultimately the people at the club decided they weren't going too big capacity wise. Theoretically there's room. There always was.
I think the initial design (and indeed one of the main motives to go to BMD) was for if we'd gotten the Commonwealth games. That would've come with a lot of additional funding. Unfortunately, that got brought forward 4 yrs due to Durban dropping out and Brum (with its more advanced bid in the now shorter window) won the almost £800m local and national government funding.
There was then a few months delay following that decision, and another consultation, after which the 52,888 capacity emerged, almost out of nowhere.
This was questioned at a few shareholders meetings at the time, with a mixture of responses. The club said that it had even been challenging to model people-movement around the site at the lower capacity.... we asked why they had initially designed it bigger then? They couldn't really answer..... I think it was at a later meeting that Colin Chong also mentioned that there had been some concerns about potential post-match congestion immediately outside the dock wall.... this may have been in relation to the Stanley Dock bridge, although I don't remember him naming it directly. There may have also been some stadium capacity consideration due to the transport plan, which no doubt would've been due to benefit from a large cash injection, if the CWG bid had been successful. All talk of a station at Vauxhall vanishing at the same time.
Stadium construction cost can rise exponentially with capacity. A 10-20% capacity increase could mean a 20-40%+ construction cost increase..... and if they got their tkt demand calcs wrong and created an over supply of seats, that scope to really control ticket prices to squeeze their asset, might also have been lost at the higher capacity. So without that additional funding, all the economic forces were probably pointing towards a lower capacity by that point. Let's face it, the financial model was non-existent and entirely based on "Bank of Daddy", with not a single major financial institution attracted throughout the process, and even when contruction was well under way. As it turned out, 52k nearly buckled us completely. It saw off our owner with a massive loss and even bankrupted one potential buyer in the process, leaving the club with various high interest loans keeping us and the stadium project afloat.