Downing Street believes rebel MPs will try to make a move to stop a no-deal Brexit in the second week of September, with the EU unlikely to respond until after that battle has played out.
A senior government source said the date for a parliamentary battle was expected to be 9 September a week after MPs return from their summer break.
Boris Johnson may meet key EU leaders, such as Angela Merkel and Emmanuel Macron, but not Ireland’s Leo Varadkar, ahead of the G7 summit in Biarritz, France at the end of August.
However, No 10 is not expecting any breakthrough until the EU has seen what happens in the first weeks of September, when a cross-party alliance of Tory and opposition MPs try to take a no-deal Brexit off the table.
The EU is adamant that the backstop is not up for renegotiation but the senior government source said there is still hope in Downing Street that a deal is possible if it becomes clear that parliament could not prevent no deal on 31 October.
Labour has been mulling an immediate confidence vote in Johnson’s government in the first week of September but they will only do so if they have enough Conservative MPs on board who are willing to bring down their own prime minister.
Rebel Tory MPs, led by Dominic Grieve and Philip Hammond, are working behind the scenes over the summer to stop a no-deal Brexit.
They have explored collapsing the government and setting up an alternative, temporary “unity government” to request an extension to article 50 but Labour has made clear it would not support a centrist candidate, such as Ken Clarke or Yvette Cooper, to be temporary PM.
Instead, leading Conservatives in the “no to no deal” campaign are prioritising legislative routes to blocking a no-deal Brexit on 31 October.
Downing Street expects 9 September to be the first opportunity for a legislative battle, as the government is bound in law to provide a report updating on Northern Ireland on 4 September and to then debate it in parliament for five days.
The prime minister’s official spokesman said Johnson remains “very clear in his determination to want to get a deal”. “He is very clear in his determination to want to get a deal. He believes a deal is in the UK’s and the EU’s best interests and he has said he will be energetic in pursuit of a deal.