Sounds like a massive rent seeking scam to me.

From The Guardian:

Countries and organisations planning to host events at vital UN climate talks in Glasgow next month have said they fear that increased costs at this year’s event will cause problems for developing nations.

Organisations say they were told that a combination of Brexit and the pandemic were to blame for the high costs. It comes after the Financial Times reported that one organisation was quoted nearly £500,000 for its space.

Sure, post-Brexit, wages for skilled labour have gone up (that was an argument FOR Brexit) but what you pay for a stand is just rent; if the real costs of having your stall fitted out go up, then rents would go down. And the rental value is dicated by how many extra ‘customers’ you will get by exhibiting.

As Treasurer for the Labour Land Campaign, I had to sign off a payment for our stand at this year’s Labour Party conference, that was a couple of grand just to have a table with leaflets for two or three days.