WHEN the Roman emperor Vespasian introduced a tax on public urinals in 74AD, his son Titus questioned whether it was an entirely seemly way to raise funds.

His father’s reply is with us still, Pecunia non olet, or “money doesn’t smell”.

The origins of wealth don’t matter, only wealth itself, was his philosophy.

But what may have worked for Roman emperors doesn’t suit modern politicians.

Where our MPs and MSPs get their donations matters because it reflects on their judgment and their willingness to put pounds before principle.

When the Better Together campaign accepted £500,000 from Ian Taylor, the boss of the controversial oil trader Vitol, the SNP and other Yes supporters rightly criticised it.

It became one of the biggest rows of the first phase of the referendum.

When Danny Alexander, the former LibDem cabinet minister, accepted £1000 towards his re-election campaign in Inverness from a Tory donor, his judgment was criticised.

Likewise, when this paper revealed the SNP MP Ian Blackford took £3000 from a Tory hedge fund manager for his election campaign in Skye, it was his turn to come under scrutiny.

Now David Mundell, Scotland’s only Conservative MP and the default Scottish Secretary, is the one facing questions.

As we reveal today, Mundell has accepted £10,000 from a company called Stridewell Estates Limited owned by Conservative party donor Brian Gillies.

Stridewell’s entire turnover comes from renting out a single shop - a pawnbroker’s in a depressed part of Cowdenbeath.

It is a very short chain that links the poor people of the town, driven in desperation to pawn their goods, with thousands of pounds going to Mundell and his Conservative colleagues.

Given Tory policies are causing much of that hardship, it looks as if the party is profiting from the misery it is itself inflicting, a startlingly ugly picture even in this age of austerity.

There is no suggestion that Mundell, or his donor, or the pawnshop have broken the law.

But it shows the Scottish Secretary to be remarkably lacking in either judgment or curiosity.

Accepting money derived from a business synonymous with human misery since the time of Dickens is no way for the most senior MP in Scotland to behave.

The Tories are already a damaged brand in Scotland, despite the strenuous efforts of their leader Ruth Davidson.

Mundell has made her job harder, and entrenched the Tories’ reputation as the nasty party