You’re tapping away on your computer at work, polishing a memo, finishing the research or doing some clever stuff with spreadsheets. You’re not alone. There’s the new guy looking over your shoulder – Gordon’s guy. You’re meant to be having a drink later with a friend from another company. You could just flick them an e-mail. But you know better. The last time you used your computer for “significant” personal reasons, Gordon’s guy punched the air, yelled: “Yes!”, and handed you a bill for £160.

This scenario may be a little far-fetched, but the thrust is not. Budget fine print would indeed allow Gordon Brown to tax employees such a sum if they used their work computer for non-work reasons. Employers would have to pay an extra £51.20. A tax on poorly worded e-mails (the syntax) is entirely understandable, but the Treasury’s contempt for companies and their employees is all too obvious.

Under the plans, companies would have to act as computer snoopers. It is hard to conceive of a less productive use of their time. Besides, the construct is based on a wholly outdated idea of work and play, where the former happens from 9am-5pm, while the latter is locked out. Does Mr Brown never use his computer to check the Raith Rovers team news? If not, why not? To see what’s on at the cinema? Or to invite the neighbours round at the weekend? Perhaps not.

Treasury officials have promised to take a “practical” view of how much private use should be regarded as “significant”. The most practical approach, when the issue is debated in the Commons today, would be to withdraw it. We are watching.