Yes, the maximum fine for no MoT is £1,000. So is the maximum for speeding (unless on a motorway, when it is £2,500) but few, if any drivers are fined anything like that sum.
The vast majority of No MoT cases are dealt with by way of a fixed penalty (£100 - no endorsement/penalty points are available for the offence). Unlike speeding there are no grades of seriousness about having no MoT - you either have one or you do not. For that reason very few end up in court and those that do are usually accompanied by more serious offences (the most popular "trilogy" being No Licence, No Insurance and No MoT).
Those that are dealt with in court usually see a maximum fine of half a week's net income (reduced by a third for a guilty plea) although very often, when there are accompanying offences, many are dealt with on a "totality" basis and may simply see a token fine of £50 or so imposed in addition to more substantial fines imposed for the more serious offences.