Image source, Reuters

Most of the focus will be on the Commons chamber today - but there is also a lot going in the committee corridors. Foreign Secretary Philip Hammond is appearing before the Foreign Affairs Committee to talk about developments over the summer. We would imagine Syria will dominate, after Monday's revelation that two British citizens fighting on behalf of the self-styled Islamic State militant group were killed by an RAF drone strike in Syria last month. MPs will likely press for more detail about the mission, its legality and its repercussions for Britain's wider military role in the region. Then there is also the minor matter of the EU referendum, with the government on the back foot after its Commons defeat over so-called purdah rules. Expect a lively session. 

Image source, AFP

The migration crisis has dominated domestic and European politics over the summer and is likely to figure prominently in the leaders' exchanges at prime minister's questions. European Commission President Jean-Claude Juncker has just told the European Parliament that the European Union's response will be "swift, determined and comprehensive", with an additional 120,000 additional asylum seekers being distributed among EU nations under a system of binding quotas. The UK is not part of this scheme but David Cameron's plans to take a further 20,000 refugees by 2020 is likely to come under further scrutiny in the Commons later. 

Before PMQs, David Cameron will lead tributes to the Queen in a special session in the Commons to mark her becoming the country's longest-serving monarch. The Commons schedule has been rearranged to recognise this significant moment in British history, with MPs being given 30 minutes to offer their good wishes on the occasion of the sovereign's 23,226th day on the throne. 

Welcome to our coverage of Wednesday's events at Westminster and in politics at large. The highlight of what looks like a busy day is the first Prime Minister's Questions since the summer recess. It's also the last time that Harriet Harman will cross swords with David Cameron, as Labour elects its new leader on Saturday.