Falsifying document re finances - what happens?

[Cabrinha]

My STBXH has doctored a letter about an insurance payout, sent to my solicitor as part of financial disclosure.
I'm going to speak to solicitor on Monday for advice, but the way forward will probably be a text from me (we've done all negotiation directly) saying "don't take the p, send in the real amount".
But I'm curious... what is that, in legal terms? Fraud, contempt of court?

Thanks if anyone knows!

[IainStirling]

Try posting in legal.