Higher rate taxpayers personally benefit from this tax relief. Anybody who is a taxpayer can give money to a charity under the Gift Aid scheme. If that is done the charity can reclaim the basic rate tax paid by the taxpayer from HM Revenue & Customs. For a basic rate taxpayer that is the end of the story. For each £1 they give the charity claims back the basic rate tax at 20% - meaning they reclaim 25p (the £ given is net after tax so the pre tax amount presumed to be given is £1 divided by 80% which is £1.25, with 25p being the tax reclaimed). For a higher rate taxpayer this is not the end of the story. If they put the gift on their tax return then they get tax relief for the donation at their full marginal rate of tax. So a 50% rate tax payer who gives £1 to a charity under Gift Aid is still deemed to have paid over £1.25 with the charity reclaiming the 25p in tax but the taxpayer claims relief on the higher rate sum at 50%, meaning that they can claim a refund of 62.5p. The charity has already had 25p so the higher rate tax payer cannot get that back and so instead they benefit by 37.5p (62.5p less 25p). This means that 50p taxpayers actually personally benefit by tax refunds of greater amount than a charity does when they gift money to charity.The first sentence is nonsense. Giving a pound to charity and getting 37.5p back isn't a personal benefit, it's a cost of 62.5p.
When I earned a salary that Murphy would think outrageous, I used a Payroll Giving scheme, by which my employer paid a monthly amount from my gross salary into a charity account in my name, from which I made donations to charity. Income tax was deducted from my salary net of this amount. It's pretty hard to detect where I can be said to have benefited personally from the tax relief. Payroll Giving works differently to the mechanism Murphy describes in that the charity can't claim Gift Aid: I don't think it meaningful to say that I was getting it.
What Murphy means, if he means anything, is that it costs a higher-rate or additional-rate taxpayer less of their net income to give a pound to charity than it costs a basic-rate taxpayer. If you see this as purchasing a sense of inner virtue, something like buying indulgences, then that does reduce the price. On the other hand, a rich person probably needs to make a larger donation to achieve a given level of contentment from it. Similar considerations would apply to the benefit if any of being seen to give the money (Matthew 6:3 has pertinent advice). And few of us think givers to charity deserve to have their motives closely examined.
Murphy's views on tax reliefs generally seem to assume that whatever the prevailing scales of income tax happen to be, those scales applied to one's gross income give a sum which is rightfully the property of the state, and any relief is therefore a gift from the state to the taxpayer. It's far from obvious to me that this is the best way to look at it.