For every £1000 lost in tax evasion, the government spends less than a penny on advertising campaigns to ask people nicely if they would refrain from cheating on the system.
For every £1000 lost to fraudulent benefit claims, the government spends £5 on advertising campaigns to get people to inform on those who cheat the system. And for every one of those £1000s lost, the government saves £12000 in unclaimed benefits. So, benefit fraud, whilst entirely wrong, could be seen to have a mainly negative effect on the economy compared to, say, not paying taxes.
For every £1000 lost to procurement fraud in central and local government, the government, for obvious reasons, spends nothing on advertising.
The country loses, by even the lowest plausible reckonings, some £1.5 billion a week in tax evasion. That's higher than the ANNUAL figure lost in benefit fraud and the same amount as the ANNUAL figure lost to procurement fraud.
My house is on fire. It's been set alight by arsonists, people known to me.
Do I a) Go after the arsonists or b) Throw petrol on it, c) attack the firemen and accuse them of setting alight to get more work or d) spend every spare penny I have asking the arsonists to think of people who we mutually loathe so we can blame them. Or e) a mixture of b,c and d.