However, this week a leaked Labour document suggests that Khan is not a close ally of the Labour leader.
Farming, construction and health care in the southern states, which rely on migrant labour (documented or otherwise), will have a smaller pool from which to recruit.Or will they?
At least two cabinet ministers dropped heavy hints about May this week and a Labour document appeared to confirm it would be the date.
Brandishing a copy of the Labour document at first minister's questions, Dugdale pressed John Swinney, the deputy first minister and finance secretary, to explain why the Scottish government had not published any recent oil and gas report.
An internal Labour document sent to the party's MPs has urged them to combat the electoral threat from Ukip by talking about the pressures immigration places on services such as health and housing.
In a speech to the Centre for Opposition Studies, Crosby said the Labour document showed the party was still making the mistakes that contributed to it losing elections in 2010 and 2015.
It is a crude way to measure commitment, but it is revealing to see that there are seven mentions of the word "inequality" in the Conservative manifesto, and not one in the Labour document; and while the word poverty is used 18 times by Labour and five times by the Liberal Democrats, the Conservative manifesto has 20 references.
A Labour document, published today in the leftwing weekly Tribune, says the national selection panel will "determine the length of each individual selection timetable, longlist and then interview aspiring candidates, draw up a shortlist for aspiring candidates which will be consistent with the decision of the late retirement panel".
In the final version of the Refounding Labour document put to the conference on Sunday on a take-it-or-leave-it basis, the party has agreed that if national and local parties can recruit more than 50,000 registered supporters (not party members), this will trigger these supporters being given 3% of the electoral college.
Nancy Platts, the party's candidate in Brighton Kemptown and Peacehaven, told the meeting at the House of Commons on Monday that she was furious over a leaked internal Labour document which appeared to suggest that candidates should discuss other areas of policy if voters mention immigration.
