LONDON, Sept 24 (Reuters) - Electronic passport gates at Britain"s airports failed on Friday, causing chaos at London"s Heathrow, where long queues filled immigration halls and some passengers were detained on aircraft until space inside was available. Britain"s interior ministry said a technical issue had affected e-gates at a number of ports of entry. "The issue was quickly identified and has now been resolved," it said in a statement. One passenger at Heathrow said it was chaos in the terminal, with space to queue rapidly running out. The e-gates are staffed and operated by Britain"s Border Force, a department of the interior ministry. Passengers at Heathrow had already endured lengthy queues this summer as staff struggled to process COVID-19 documentation in addition to passports and visas.