Aug 12 (Reuters) - London's FTSE 100 rose on Friday after data showed Britain's economy contracted by less than feared in the second quarter, while drugmaker GSK rebounded after heavy selling this week on litigation concerns.
The FTSE 100 rose 0.3% by 0711 GMT and was on course for a fourth straight weekly gain, online betting while the FTSE 250 midcap index slipped 0.1%.
The Office for Online Betting National Statistics said the UK's gross domestic product fell by 0.1% in the June quarter, compared with forecasts for a 0.3% drop.

However, the data still pointed to growing weakness among consumer-facing sectors of the economy, like retail and restaurants, that are most exposed to a worsening cost of living crisis.
Drugmaker GSK rose 3.8% after shedding about 16% in the past two sessions on concerns about U.