Corbyn asked for five commitments
In a letter to Theresa May (with an accompanying photo op), Labour leader Jeremy Corbyn asked for five legally binding commitments that it would require to get his party's support.
A "permanent and comprehensive UK-wide customs union", including a say in future trade deals.
Close alignment with the single market, underpinned by "shared institutions".
"Dynamic alignment on rights and protections", so that UK standards do not fall behind those of the EU.
Clear commitments on future UK participation in EU agencies and funding programmes.
Unambiguous agreements on future security arrangements, such as use of the European arrest warrant.
The letter and Tusk's endorsement of it puts May in a tough position. If she brushes it off then it's a slap in the face to the EU, who can then say that there was a way through that she ignored.
If she goes along with Labour it could alienate her own party and would lead to at least a few dozen of them abandoning her, if not more.
Ultimately, the choice she may have to make is to accept Corbyn's deal -- albeit after some negotiation -- and get Brexit through, then walk away or call new elections.
The BBC's Laura Kuenssberg thinks it's possible but the risk is that Labour support doesn't come through and May loses everything.
