Boris Johnson has made a good start, but he is heading for a fall

Editorial: When MPs return to Westminster on 3 September, the prime minister will be reminded daily that his government is severely constrained

Boris Johnson expects talks with EU on the Irish backstop 'in the coming weeks' and returns Donald Tusk's warning of going down in history as 'Mr No-Deal Brexit' (Getty)

Boris Johnson has had a good start as prime minister, on his own terms, but it is hard to escape the feeling that he is heading for a fall.

He has now been in post for a month, and his boisterous assertion that Britain will definitely be leaving the European Union on or before 31 October has rallied Eurosceptic opinion. The Conservatives are enjoying a modest revival in the opinion polls as former supporters of Nigel Farage’s Brexit Party decide that they like what they hear from 10 Downing Street.

Now for the hard part. So far, Angela Merkel and Emmanuel Macron have been polite, but have offered no real prospect of a withdrawal agreement that is much different from Theresa May’s.