** UK oil and gas firms trading in green after an Israeli strike on Iran sparked concerns that renewed tensions in the Middle East could affect gas supply
** FTSE 100 .FTSE constituents BP BP.L up 2.3% and Shell SHEL.L up 1.6%, stock among top gainers
** Shares of North sea-focused oil and gas producer Serica Energy SQZ.L up 2.5% at 166p, highest since June 2024
** Shares of North sea explorers EnQuest ENQ.L, Ithaca Energy ITH.L, Harbour Energy HBR.L up between 3.1% and 4.3%
(Reporting by Nithyashree R B)
((NithyashreeRB@thomsonreuters.com;))