From now the day light saving system is followed in Europe and US and the session and gap times are as follows:
JAPANESE SESSION - 00:30-07:00 GMT
GAP TIME - 07:00 -07:30 GMT
EUROPEAN SESSION - 07:30 -13;00 GMT
GAP TIME -13:00 -13:30 GMT
US SESSION - 13:30 - 20:30 GMT
GAP TIME - 20:30 -00:30 GMT
to read the intentions of the players it is better to follow their timings of the sessions.They are known to make false move during gap times,session start and session close time stop hunts on the upside above high or on the downside below low,during gap time they mostly handle crosses by making contrarian moves.
Regards
Dr.Sivaraman
Operators' intentions read by 

Doc,
Your gap time before UK has finished just before UK open at 8am UK time, are you saying now gap time is the first 30 mins of UK Open ????
Dear
07:00 -07:30 GMT is the gap time before the start of EUROPEAN session.You can convert to your local time to understand or track the market in GMT time by comparing current GMT time with your local time.
Regards
Dr.Sivaraman