Put a kilt on it, laddie – or so old-school news editors used to say when they needed a Scottish angle to an essentially Westminster story.

The cash-for-teas row has a similar air of contrivance about it.

Alex Salmond stands accused of holding a "secret" meeting with wealthy donors, Chris and Colin Weir, over tea at Bute House only days before they gave £1 million to the SNP. Labour has compared tea-gate to the cash-for-access scandal following the resignation of the Tory fundraiser Peter Cruddas, who was recorded apparently offering favours to potential business donors. (If only Greggs had got their money in, they might have been able to stop that hot pasty tax.)

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But the difference is that the Weirs are long-time SNP supporters enriched through a lottery win rather than businessmen seeking to promote their commercial interests through contact with ministers. It's hard to imagine them ever appearing on David Cameron's "dinner list". Still less that they'll be rewarded with an appearance on the Queen's honours list. Nevertheless, there's an important issue here: money talks in politics – always has. But money talks even louder in a small country like Scotland.

Or Ireland. As Scotland contemplates independence, we'd do well to examine the report of the Mahon Tribunal into political corruption in Ireland, published last week. This had already prompted the resignation of the former Taoiseach, Bertie Ahern, following revelations about cash payments in the 1990s – though Mr Ahern insists he did nothing wrong. The sheer scale of the corruption exposed by Mahon has shocked a voting public which had few illusions about the probity of their politicians. The report concludes that corruption is "so entrenched it is transformed into an acknowledged way of doing business, specifically, because corruption affected every level of Irish political life". The Tribunal alleged that the former European Commissioner and Fianna Fail minister Padraig Flynn – a politician I interviewed in Brussels not so long ago – had used political donations to buy himself a farm.

As I say, it is ridiculous to equate tea with the Weirs with the corruption of an entire political class. But the warning signs are there. As the SNP has become the dominant political force in Scotland, money has come sniffing around the door at Bute House. The First Minister insists he gave the press baron Rupert Murdoch nothing more than a Tunnock's caramel wafer when he entertained him at Bute House in February, but it subsequently emerged that Mr Murdoch has been in Bute House more times than the First Minister's favourite carry-out curry.

The SNP leader had already raised eyebrows through his apparent support for the loud-mouthed casino owner Donald Trump and his Aberdeen golf project. One of the biggest donors to the SNP is, of course, multi-millionaire Brian Souter of Stagecoach, a man of intensely conservative opinions. Some have suggested that the SNP's sotto voce support for gay marriage is down to their reluctance to antagonise their paymaster. Actually, this almost certainly has more to do with Mr Salmond's reluctance to antagonise the Roman Catholic Church.

The problem with political corruption is that it all starts so innocently, with social contacts born of mutual respect between wealthy individuals and politicians who desperately need money to fight elections. Naturally these big donors have their own big ideas, like cutting taxes on the rich, or freeing up planning regulations, or blocking wind farm developments. It's only natural they get a fair hearing for their views since they've paid so much money to be in the presence of political greatness. That's when schmoozing ends and cash-for-influence begins. Before you know it Bernie Ecclestone is banging on your door wanting Formula 1 exempted from the ban on smoking adverts.

In small countries, personal networks have always cut across the formal boundaries of public life. In Ireland, the closeness of the political and business elites turned into a form of financial cronyism called "cute hoorism". No democratic political culture is ever going to be immune from the cash nexus so long as politicians need to raise money to survive. Political parties are no longer mass organisations financed by membership subs.

Labour gets a great deal of its money from the trade unions, which is a conflict of interest that may no longer be tenable. The Tories traditionally look after their own in the City of London and in the boardrooms. Their decision to axe the 50p tax band – highly damaging to the Tories in the polls – was canvassed by precisely the businessmen who donate to the Tories. No money changed hands but the top people got to keep a bit more of theirs, and they'll no doubt show their gratitude. As Sir Christopher Kelly of the Standards Committee pointed out in November: "All three parties now depend on very large donations from a small number of rich individuals or organistions. That cannot be healthy for democracy."

State funding of political parties may seem the only solution but it carries its own problems. The wealthy can channel their cash, as in America, into supporters' organisations which, effectively, pay for television party political broadcasts. State funding can also institutionalise party dominance. How do small parties like the SNP get in the door if they lack the public money that comes from having a big vote? These are difficult questions, but not insoluble ones. Donations should surely be capped for a start at £10,000, as recommended by Sir Christopher. State funding should be matched to party membership, to encourage parties to reconnect with voters.

But the best prophylactic against sleaze is transparency and openness about donations, loans, dinners, freebies and, yes, tea parties. We need to know who is schmoozing whom. And actually we have a lot of transparency in Holyrood already. Some say too much. Remember how the Labour leader, Wendy Alexander, had to resign in 2008 over donations solicited from a businessman who was not a British national? I can think of few politicians cleaner than Ms Alexander, and I could understand her bitterness at being cast out of public life with a cloud over her head. But if it's any consolation, her departure may be what keeps Scottish politics clean and above board for generations to come – a kind of political martyrdom on the altar of transparency.