proving lies in court

Hi,could anyone tell me what sort of information or documentation i can obtain to prove my STBX is lying about,regarding his income,car values,outgoings,self employed/cash in hand work he carries out.
What is permissable and how i might go about it in the correct way without it being a criminal offence.

Cash is hard.
Income from self employed is on his Self Assessment.

Car values, just put the reg in webuyanycar.com - but it may have outstanding finance that he can produce from the finance company.

Income from self employment,which is pretty much all cash in hand,isn't on his self assessment.
He lies about what he earns,jobs he is doing etc...cooks the books,only declares what he chooses to.
That is the point i am trying to make.
What sort of proof can i use legaly.

Word of mouth ?
Ask the people he carried the work out for ?
Take photos ?

Have you exchanged form E's as he would have to show 12 months of bank statements. This may show his standard of living, unless he pays for everything in cash?

hope this helps....

my partner has the same issue with her ex - he is a taxi driver and says only earns £100 per week to get away with paying £5 per week child maintenance for 2 kids!!! But his household expenses are around £200 per week??!!

This appears to be the route many take in order to save a few quid...simply lie through their teeth...quite astonishing particularly when children are involved.
I think these people who tell lies begin to believe the lies themselves.
Quite despicable in my book...i for one do not believe or trust or word that comes out of ex's mouth...if they dig deep enough they will fall in!!

I was just trying to establish what would be acceptable proof of STBX's income.
Yes he will have 12 months bank statements but that doesn't help when it comes to the cash he earns,which is 90% of his income.
He doesn't declare all his earning on his self assessment and didn't disclose a true figure during mediation.

I am aware of many jobs he has carried out but not declared the income from them.
How do i make the courts aware of this,what sort of proof can i get/use ?

I wouldn't mind,but it isn't because i want maintenance or anything from him, i just want to prove he is not the "hard done to,poor penniless,i've got nothing left" person, he keeps making out he is.

So you go through the bank statements flagging up any large discrepancies...it will be obvious to any lawyer worth their salt that his lifestyle does not match what is going into the bank account...they have seen it all before and then some!