What is, and what isn’t business mileage?

I thought it was a simple if it’s between home and office, it’s commuting. If it’s home to site or site to home (each site would only get a handful of visits a year) it’s business.

But there’s a suggestion in the office, that it’s not business mileage if it’s “similar” to your commute.

Is this a company thing or an hmrc thing?

An example; If your commute is ten miles but one day you travel direct from your house to a business meeting and it’s ten miles, you can’t claim business mileage.

If it was twelve miles to the meeting, you could claim two miles.

I thought it was measured from your regular place of work even if you leave directly from home? Or am I misremembering?

I think it’s only if you pass close by. AFAIK it’s a policy used by some employers called triangulation.
A “similar distance” is weasly company bollocks IMHO.

Triangulation

Triangulation is the name given to the practice whereby employers will only reimburse the cost of business travel by reference to the lower of:-

the journey between the permanent and temporary workplace; and
the journey between the employee’s home and the temporary workplace.

For example, when an employee passes close to his permanent workplace on route to a temporary workplace, even though he does not stop at the permanent workplace under a triangulation policy the employer would not pay any mileage allowance for the part of the journey equivalent to the employee’s ordinary commute.

However, HMRC would regard the whole of the journey as business travel and hence the whole journey would be eligible for tax relief. Therefore, if the employee was using his own car for the journey, he would be eligible to claim Mileage Allowance Relief for the part of the journey that was equivalent to his ordinary commute.

That sounds about right wrecker. Where is that quote from? Might be time to have a word with the union as the message was written to suggest that we might be back taxed if we don’t use their similar journey method.

Toyota guide;
http://taxability.toyota.co.uk/DefinitionofBusinessMileage_26.html

This should be a piece of cake to a decent union type.