THIRTY-ONE people had to be treated in hospital after ammonia leaked from a refrigeration unit designed to keep The 02's ice rink cool.
The O2, the famous venue for concerts thrown by Prince and The Rolling Stones, had to be evacuated at 8.30pm last night after the refrigeration unit's alarm went off.

The London fire brigade arrived at 8.45pm to the Greenwich venue to attend to the leak coming from the arena's refrigeration plant room. Firemen deemed the building safe at 10.30pm.

The building reopened as usual at 10am the following day (October 30). O2 confirmed the investigation involving Greenwich council is ongoing and the reason for the leak has yet to be identified.

The O2 arena ground can be changed between ice rink, basketball court, exhibition space, conference venue, private hire venue and concert venue within hours. This is possible as the bottom layer of the arena ground is an ice rink which is constantly maintained. This can then be covered with insulation material to become a dry surface. A wooden stage or any other material for any event can then be laid out on top of this.

A spokeman for O2 said 'Last night there was a minor ammonia leak at The O2. 'The building was immediately evacuated and some members of staff were taken to hospital as a precautionary measure. They are all out of hospital now and The O2 is open today as normal”.