What does the House of Commons 'Clerk' actually do?

The Clerk of the Commons, David Natzler has given BBC 5 live an insight into his day-to-day duties.

Mr Natzler is Parliament's most senior legal and constitutional adviser and has been working at Westminster since 1986.

Speaking to Emma Barnett, he explained how one of his jobs is to advise the speaker to make sure he gets the rules right.