2 MIN READ (For a Reuters live blog on U.S., UK and European stock markets, click LIVE/ or type LIVE/ in a news window) * Both FTSE 100, FTSE 250 flat Sept 3 (Reuters) - London’s FTSE 100 struggled for momentum on Friday as banks and energy shares countered gains in miners, while investors awaited a reading on August service activity data later in the day. The blue-chip index traded flat, as heavyweight oil majors BP PLC and Royal Dutch Shell slipped 0.5%each after flagging impacts from Hurricane Ida. Banks and life insurers slipped 0.3% and 0.5%, respectively. Although losses were capped as global miner BHP Group rose 1.3%, rebounding from a 5.6% fall in the previous session. The wider mining index gained 0.2%, tracking metal prices higher. The domestic focused mid-cap FTSE 250 index remained unchanged. The IHS Markit/CIPS services Purchasing Managers’ Index (PMI) is likely to fall to 55.5 last month from 59.6 in July amid supply-chain bottlenecks that also stunted British manufacturers’ recovery from the COVID-19 pandemic in August. Petrofac Ltd rose 1.5% after the oilfield services company secured a $100 million worth contract with Zallaf Libya Oil & Gas Exploration and Production company. (Reporting by Devik Jain in Bengaluru; Editing by Saumyadeb Chakrabarty)