Labour and the Liberal Democrats' rocky relationship is becoming increasingly inconsistent, with conversations now revealed as having taken place at the highest level.
Attention on contact between the parties' senior figures began this summer with the revelation by shadow chancellor Ed Balls that he has been in frequent contact by text with Lib Dem business secretary Vince Cable, a former SDP politician, who has spent the summer undermining Lib Dem leader Nick Clegg.
Labour's deputy leader Harriet Harman has since made clear in an interview with the Independent newspaper that she is not a supporter of "cosying up" to the Liberal Democrats, on the basis that Labour may rely on the Lib Dems in the event of another hung parliament in 2015.
Nevertheless, Lib Dem deputy leader Simon Hughes – the most senior member of the party who is not formally a member of the government – has now himself admitted having texted Ed Miliband.
Such moves could appear to leave party leader Nick Clegg, who is seen by many voters as being wholly associated with his coalition partner David Cameron, extremely isolated.
So on BBC1's The Andrew Marr Show this morning Clegg responded by revealing he has also been in contact with Ed and David Miliband, Tony Blair and Peter Mandelson in recent weeks.
"Grown-up politicians talk to each other across party lines," he said.
Ed Miliband has appealed to disgruntled Lib Dem supporters to join Labour but has been open to negotiation over issues where the two parties are natural allies – like Britain's relationship with Europe, for example.
The two parties remain at odds over the deficit, however. Criticism of the coalition's austerity drive from Clegg's outgoing director of strategy, the former think-tank chief Richard Reeves, helped underline that point this morning.
Writing in a pamphlet published today and quoted by the Observer newspaper, Reeves stated: "For what it is worth, I think the coalition tightened a little more than necessary in the first two years; relied a bit too much on spending cuts rather than tax rises to fill the hole; and above all has taken a myopically conservative approach to borrowing for investment."
The comments were pounced upon by Labour's shadow Treasury team as a fresh opportunity to attack the deputy prime minister.
"Nick Clegg should be sorry that he didn't listen to his own adviser, and many others, who warned against signing up to a plan to cut spending and raise taxes too far and too fast," Chris Leslie said.
"The country is paying a heavy price as a result, with the economy in a double-dip recession and the deficit rising by 22 per cent so far this year.
"We need a change of course now and that must include ending the Treasury’s block on bringing forward the long-term infrastructure investment our economy so desperately needs."
Harman made clear her view that, with over two-and-a-half years to go until the next general election, the Lib Dems remained the enemy for now.
"We are not going to say the Lib Dems are a better option than the Tories. It would be misleading for voters," she told the Independent.
"There will be no cosying up to the Lib Dems. No nods and winks. No political games. No hidden agenda aiming for a future coalition."