London is in Europe as much as it has ever been. Geographically, its status hasn't changed -- whether you consider the island off the coast of the European mainland part of Europe or not; politically, its still the capital of the UK, which -- despite having voted that its government should withdraw from the EU -- remains an EU member, and not even formally on the exit path yet.
UK will also remain a member of the Council of Europe, a signatory to the European Convention on Human Rights, will probably have a Switzerland-ish deal on European trade, and will likely opt-in to a lot of European projects like the ESA and science funding/cooperation.
London is in Europe as much as it has ever been. Geographically, its status hasn't changed -- whether you consider the island off the coast of the European mainland part of Europe or not; politically, its still the capital of the UK, which -- despite having voted that its government should withdraw from the EU -- remains an EU member, and not even formally on the exit path yet.