Andy Burnham has begun his tenure as mayor of Greater Manchester by showing he’s a man of his word. One of only 69 MPs who pledged to give away their 2015 pay rise, Burnham announced early in his candidacy that if elected he would donate 15% of his £110,000 salary to kickstart a Mayor’s Homelessness Fund. He duly spent his first morning on the job out with an outreach team and restated his intention, saying “Rough sleeping and homelessness are not inevitable consequences of a 21st century economy,” indicating that the fourfold increase in people living on the city’s streets since 2010 is the result of government failure.

It’s easy to dismiss this as a savvy bit of image-polishing – inaugurating a special mayoral fund has the whiff of a personality cult about it – but Burnham’s pledge raises key questions about taxation, charity and how we fund vital services.

His approach will be familiar to Manchester’s sizable Muslim population and its Jewish community, the largest outside London. Zakat or alms-giving is one of the five pillars of Islam, and the Torah lays down clear rules on tithing. While Burnham’s Catholic background might have influenced his move – tithing is not obligatory but the church sets out a clear moral obligation to help the needy – his socialism underpins it. This is, after all, the man who based his 2010 Labour leadership bid on “aspirational socialism”, saying “I make no apology for it, rehabilitating the S-word… It is about everybody looking after each other’.

Whether we want to look after each other is another matter. The median household disposable income was up last year and the UK is consistently in the top 10 of the Charities Aid Foundation’s World Giving Index – this suggests we have money to give and seem to want to give it. Yet while over 1 million Britons donate to charity regularly through payroll giving, that raised a relatively paltry £134m last year and less than a third of people give to charity monthly. Campaigns to encourage regular giving have been in vogue in recent years. William MacAskill, Oxford philosopher and driving force in the effective altruism movement, co-founded Giving What We Can in 2009, urging people to give 10% of their income to fund charities that have been proven to have the greatest impact. The coalition government, meanwhile, swapped altruism for the promise of a 4% reduction in the rate of inheritance tax for those who leave 10% of their estate to charity, and the three main party leaders all signed up to the Legacy10 campaign.

However, as the coalition came to its end, “charity” became a dirty word in Britain. The suicide of British Legion volunteer Olive Cooke sparked tabloid headlines about the nonagenarian being “hounded to her death” by charity begging letters (the inquest named her depression and cancer diagnosis as the only relevant factors), and investigations by the Fundraising Standards Board and the Information Commissioner ensued. This was swiftly followed by the collapse of Kids Company. While the right-wing press have long represented charity CEO salaries and international development aid as twin blights (remember the Ethiopian Spice Girls), research carried out by the Charity Commission last year found the trust the public have in charities had reached an all-time low.

The attitude to charity in the US, meanwhile, where Mormons and Southern Baptists use tithes, contrasts sharply with our own. Its well-developed philanthropic culture had Bill and Melinda Gates and their declared aim of giving 95% of their fortune away at its pinnacle. On measures of individual giving and volunteering, US citizens rank highly. Yet this is set against a deeply tax-sceptical society, where Obamacare could be figured as coerced charitable giving rather than a public health scheme. This “giving with one hand and taking away with the other” situation is illustrated by Donald Trump donating his presidential salary for the first quarter of 2017 to the National Park Service while simultaneously proposing to cut $1.5bn from the Interior Department, which oversees the service.

Indeed, tax is charity’s estranged twin, and where historically non-payment of tithes carried the threat of sanction, tithing was the original taxation system. Clement Attlee, the architect of the welfare state, said: “Charity is a cold grey loveless thing. If a rich man wants to help the poor, he should pay his taxes gladly, not dole out money at a whim,” and clearly it is government that holds the power to enact lasting change in people’s lives. But the very real prospect of at least a decade of rightwing government programmed to cut public services to the bone changes the status of direct charitable giving.

While ideas of hard-working families’ money disappearing into the insatiable maw of the exchequer continues to be an article of faith for the right, and the left maintains that the essential principle of core services being the state’s responsibility shouldn’t be undermined by charity, the tensions between what we must pay and what we should pay are going to become ever more pronounced. As Burnham urges others to donate a proportion of their own salary to the new mayoral fund and make a difference on the ground in Manchester, the old adage that charity begins at home may well have to be revived if we are to protect the most vulnerable people in our own communities.