In their first joint television appearance, the Chancellor and the Prime Minister were keen, however, to show their lighter side to relay one of their flagship policies directly to millions of voters.
During their leadership squabbles over the past few years, Mr Blair may well have wanted to slap Mr Brown's sallow chops, Eric and Ernie style, but both men were determined to put on a united front for ITV's This Morning programme.
Displaying his own gentle gift for understatement, Rich-ard Madeley began proceedings by referring to the reported behind-the-scenes rifts between the pair. "To be honest, is there an undercurrent here that you are demonstrating that the two of you work in harmony, against all the rumours to the opposite?" he asked.
Momentarily thrown, Mr Blair sputtered: "Well, the rumours have never been true." Like the true professional that he is, the Prime Minister then recovered his composure sufficiently to advocate the joys of the working families tax credit.
The credit is as ferociously complex as its name suggests. The job of explaining it is a daunting one even in the House of Commons, let alone on daytime television. Wedged neatly between More Ways to Make Money from Your Dog and Nicky Clarke's Guide to Putting Body in Your Hair, "Call Tony and Gordon" was a charm offensive up against stiff competition for the viewers' attention.
But Mr Blair is, of course, a veteran of the cheesy, sofa-side chat shows and was welcomed like an old friend by Richard and Judy, the king and queen of soft furnishing journalism. By contrast, the Chancellor's reputation has been based more on his Heathcliffian dourness and a personality that has fewer frills than a Doncaster KwikSave. Yet as he and Mr Blair fielded calls on the new tax scheme, the jaw appeared to soften, the voice took on a jovial tone and the public was treated to that rarest of muscular movements: a smile.
Dealing deftly with queries from Linda in London about housing benefit and from Alison in Hertfordshire about her part-time hours, the Chancellor appeared to revel in his new-found good humour. He smiled, joked, even laughed as the calls came in from across the nation. "You will be better off," he said, time and again, as he and Mr Blair recited their mantra of "Making Work Pay" like a game show catchphrase.
Only one hiccup appeared in the form of Hayley from Essex, who nearly ruined things by complaining that her part-time job prevented her from receiving help with her university fees.
But before anyone got too embarrassed, the pair were thanked for their appearance and Richard moved on to weightier matters. A much sexier cash giveaway, a quiz in which viewers win pounds 4,000 for guessing which dog picks up a stick, was just minutes away. "And, after the break, Fetch the Stick," said Richard.Reuse content