The bags under Brendan Barber’s eyes say everything about his first six weeks as the TUC’s General Secretary-elect. The morning we met, he had been through another exhausting night of mediation between the government and the Fire Brigades Union. Later that day, it emerged that seemingly he had broken an impasse.

That shouldn’t come as a surprise – it was as the TUC’s fixer par excellence that Brendan Barber established his reputation as heir apparent to the Congress’ top job. As John Monks’ deputy, he would work the backrooms of Congress House with skill and diligence, putting together the deals and policy documents that would help stem the seemingly irrecoverable decline of the trade union movement under Conservative rule.

Born in Southport, Merseyside, in April 1951, the son of a bricklaying instructor at a young offenders’ institution, Barber was educated at St Mary’s College, a grammar school in Crosby run by Christian Brothers. He left the area after school, but his Liverpudlian roots live on through a devotion to his beloved Everton.

He joined the TUC as a policy officer in 1975 following a year as a researcher for a training board and, before that, a gap year in Ghana and study at City university. After a spell in the industrial relations team, he became head of press and information between 1979 and 1987, and returned to head his old team before becoming John Monks’ deputy in 1993.

Given a background so deeply rooted at Congress House, there is perhaps a danger of becoming too wound up and deeply embroiled in its workings to bring a fresh outlook to the job. Yet it would be both wrong, and unfair, to characterise Brendan Barber as a TUC hack. He is very much from the same school as Monks: a moderate, a conciliator, a self-confessed ‘advocate of the partnership model of industrial relations’, who would like to work more closely with both the government and employers. His appointment has been dubbed a continuity step, and Barber admits as much: ‘Inevitably, there’s an element of continuity… but the political environment throws up very different challenges to the ones John faced in his term.’

Indeed they are. Brendan Barber has to ensure that a Labour government in its second term retains an interest in a body with which relations are historically strong, but which, in recent times, Labour has sometimes sought to keep at arms length.

He acknowledges that one of Tony Blair’s key intentions when he took over the Labour party leadership was to establish a better relationship with business, and that ‘it is essential that Labour’s reputation for economic competence is upheld’. But he feels that sometimes there is a tendency to listen to bodies like the CBI ‘with too much attention and deference’.

Many commentators have picked up on the growing distance between New Labour and the unions, a concern recently voiced by the party’s general secretary, David Triesman, who said that they were ‘sleepwalking to separation’. This was, Barber feels, ‘a wake-up call to the concerns he has from his perspective’. Nevertheless, ‘if people are sleepwalking, I want to wake them up as well.’ The relationship between the Labour party and the trade unions, he adds, is one of ‘huge strategic importance to both sides’ and not one that should be given up lightly.

Rising inequality is a recurrent theme in our conversation, and one of the challenges Barber faces is in extending trade union membership among those at the very bottom of the labour market. This casualised, contracted out, deeply insecure part of the workforce needs union protection now more than ever. As Barber says, ‘they have a depressing and demeaning experience of work.’ Yet those who fall into this bracket are less likely to be members. Fewer members at this level means less manpower for recruiting new affiliates, leading to a self-perpetuating circle of deterioration.

This, plus falling membership amongst the age group entering and establishing themselves in the workplace, should set the alarm bells ringing in Congress House. Less than twenty percent of twenty to 29 year-olds in employment are trade union members, as opposed to double that amount in the 40 to 49 age group. They are more likely to be working in areas – such as call centres or low-grade clerical jobs – where there is no tradition of unionism, than the heavily unionised factories or mines of bygone years.

How, then, is Barber going to make unions more relevant to this generation? ‘I don’t draw the conclusion that young people regard unions as being irrelevant.’ The problem, he says, is not in making unions pertinent to young people. ‘Our core message and values are relevant,’ he claims, but in ‘areas like the service sector, where there’s no tradition of unionism, we’ve got to make contact and go down there and find new ways of talking to people.’

Despite an ailing membership base, which will – without question – need to be redressed quickly and with imaginative or even radical tactics, Barber is ambitious about the scope of his brief. He rails against ‘terrible examples of corporate excess’, speaks at length about how boardrooms should have ‘greater accountability’ to their shareholders, and questions ‘the economic benefits of using PFI’.

In the past, he has spoken of the TUC as Britain’s conscience – ‘standing up to the powerful forces that make us unequal’ – but he claims that he hadn’t meant to recast the TUC as the ‘new opposition’. The intention was that as ‘the largest voluntary association of people in British life’, the TUC should mark their territory ‘as a powerful representative force’.

The TUC still has seven million affiliated members. But, as Barber approaches his imminent period of leadership, he faces testing times – even if, at first, just to find the defining theme of his forthcoming term of office.

It’s a question of vision. John Monk’s tasks were easily defined: to mark out the TUC’s territory in a hostile (pre-1997) political climate; to stem a decade-long decline in union membership; and to develop a relationship with a new Labour party leadership, then government.

Barber’s challenges are not so readily identifiable. As General Secretary-elect, he has articulated broad ambitions. In May, when he takes over, he has to decide quickly upon his ‘big idea’ for the unions: be it the expansion of membership; unionisation of ‘new’ sectors of employment; or the development of ‘partnerships’ with employers. Worthy words about corporate governance may grab him headlines now, but in five or ten years there will remain the danger – as when Monks took office a decade ago – that the position of British trade unionism will be so weakened that nobody will listen.

Nevertheless, his wish list for 2013 remains clear, and he is optimistic: ‘Full employment; bigger, stronger and growing trade with many more third world countries than we’ve got now; greater social cohesion and less inequality. And,’ he adds with a grin, ‘during John’s term of office his team [Manchester United] won the Premiership on seven occasions. So I’ll hope that during my term Everton will be similarly kindly endowed!’