No, they differ - however the 'standard' is left hand, this is to afford the P1 an uninterupted view of the airfield from the left hand seat.
The cct direction can be determined by several means when joining:
- Observe what other aircraft ae doing
- Observe the signal square markings (if the airfield has one)
- Information/ Instructions over the R/T or telephone briefing
- Information publised in UK AIP or commercial flight guides
A right hand cct may be flown for a variety of reasons e.g. noice abatement, high ground on one side of the airfield etc etc