Towards the end of a "summer of silence", the Labour Party has published figures showing that UK wages have seen the fourth-worst decline among EU nations since mid-2010.

The 5.5% fall amounts to an average pay cut of £6660 over this parliament, equivalent to a year and a half of weekly shopping runs.

But falling wages, rising living standards and a bottom-heavy job market are not just down to the Coalition. New Labour oversaw the same trend. Production per head (GDP) and earnings peeled apart in the early 2000s, living costs have since left the median wages far behind and most new jobs are now in low-wage sectors. Going further back, the share of national original income earned by the bottom 40% fell from about one-third in 1977 to under one-quarter in 2009, before the Coalition Government came into office.

For decades British governments have led working people down a path of rising inequality, falling relative incomes and living standards that don't keep up with those of the better off. Under Westminster, powers over jobs and wages are mostly left to the whim of private companies and employers. The state's prerogative is occasionally well used - such as when Labour introduced a minimum wage - but lax labour market rules and weak workers' rights permit exploitation by some employers, meaning instability, hardship and precarious lifestyles for lower-end workers.

Wages and living standards will probably be central themes of the 2015 General Election, but while Labour is right to suggest a deepening divide between lower earners and the rest of the population under the Coalition's watch, there is reason to be skeptical about whether a Labour Government at Westminster would remove it.

This is not to doubt Labour's credentials, or the conviction of its members, and Labour can win in 2015 on the back of an argument about working people's living standards. But the limits of Westminster mean there's little prospect of Labour breaking the trend of rising costs and falling wages.

As a Labour member committed to changing conditions and wages through the most viable route, bringing full powers over wages and work to Scotland seems the best way to make life better for those who work here. After a Yes vote, a Scottish Labour Government, or one with a party like Labour at least in coalition, could do more than a Labour Government at Westminster to improve working people's lives.

Having said that, some maintain key powers should be devolved to Scotland following a No vote. But the LibDems' proposals to devolve the Work Programme and JobCentre Plus give no scope to change the labour market or wages. So it falls to Scottish Labour to offer compelling reasons to vote against full powers for Scotland.

Scottish Labour's formal position will be unclear until the delayed Devolution Commission is published, but its silence on what seems to be its UK counterpart's key issue, the focus on wages and living conditions, suggests it believes jobs and pay are not a matter for Scottish politics. Likewise, when figures on rising underemployment and zero-hour contracts entered the Scottish political scene, Iain Gray meekly urged the Scottish Government to use current powers to slightly better effect. No word about labour market reform, no touching base on the purpose of Labour to transform people's conditions of employment and fight to make contracts good for workers not bosses.

The STUC is right that wages and the labour market are central to the debate about independence and further devolution; but Scottish Labour, the natural party to address them, refuses to engage. As long as it desists from showing how a No vote will result in the right powers coming to Scotland, full powers will be the most viable way to better wages and living standards for the people who work in Scotland. And as long as my party insists on excluding the labour market and other crucial issues from Scottish politics, I will have no doubt about my commitment to voting Yes in 2014.