it is highly unlikely any employer would take an ex-employee to court for failing to work their notice period.
It's unlikely but it's not unheard of.
From a legal perspective - you're contract of employment is unlikely to form the foundation for an originating claim for consequent costs (i.e. we had to cancel a train because Johnny only gave 4 weeks notice instead of 6 etc...)
I don't know where you get that idea from. It's a pretty straightforward breach of contract - you agreed to give X months' notice of resignation, but you gave none. Therefore all reasonably foreseeable and mitigated costs can be recovered.
the costs of the legal process would be far higher than the potential recovery
For very small amounts, perhaps. But particular in the case of drivers, the costs mount up very quickly. If a driver with a 6 month notice period leaves without giving notice, there could be serious losses at stake. Potentially even beyond the realms of the Small Claims Track, meaning that legal costs would be recoverable.
and from a purely practical view, how would an employer prove beyond all reasonable doubt that the costs being claimed were as a direct result of a person leaving the business inside their expressed notice period?
Quite simple - drivers have established rosters quite some time in advance; any uncovered turns as a result of someone summarily leaving will have to be covered as best as possible (often meaning that inducements are necessary, e.g. "you'll get 12 hours for this 6 hour job). It wouldn't be difficult to tally up the additional amounts paid (e.g. 6 hours' drivers wages in the above example).
It is very unlikely that a replacement driver could be trained up within whatever the notice period is.
Any good defence would argue the claimant should have suitable contingency to cover events such as staff unavailability
Perhaps, but that doesn't mean it comes without a cost. As stated above it may require offering overtime at higher rates, for example. I accept that things like Schedule 8 delay penalties and Delay Repay are going to be too remote to recover, but certainly the direct costs of replacing your labour are pretty hard to argue with.
and even if the case did proceed - there would be statutory limits on any amounts that could be claimed, with the vast majority of assumed costs being inadmissible.
There isn't an automatic statutory limit, beyond the fact that losses must be reasonably foreseeable and mitigated, as in any claim.
At very best, some TOC's have "gentlemen's agreements" between specific other TOC's (normally within the same parent company), which "bans" staff transferring between the TOC's within the agreed notice period.
This is quite common, and as you say is realistically speaking the most likely outcome.
Having said that, with due process being "conditional offer of employment" then "formal offer of employment" for a potential new employer, all the due diligence checks would have been complete and a formal offer of employment accepted by both parties prior to the existing employer contract being terminated.
It doesn't always work that way though - I certainly know of companies in the industry where it's routine for people join "on probation" which is only passed once, amongst other checks, references come back satisfactorily. So the fact that you've started doesn't necessarily mean the coast is clear.
If a former employer then passed on information afterwards, they would be leaving themselves potentially open for a claim against themselves.
Obviously it depends on the circumstances, but there is unlikely to be any liability as a result of making a factually true disclosure regarding someone's non-adherance to the notice period. It's a small world and word could easily get round.
As for injunctions, the only situations I have ever been aware of, are where there was a specific term in someone's contract that for commercial reasons - they "weren't allowed to work for XYZ Ltd for a period of XX months after leaving ABC Ltd". I've never known an injunction being issued by a Judge for not working a notice period.
I agree, it'd be pretty rare. But I would never say never; driver training etc. is an expensive and slow business and if someone suddenly quits without notice, it can leave the employer in the lurch. I don't imagine this is routine practice with most of the TOCs but I wouldn't rule it out for some of the smaller players in the industry, where one person leaving could have a really significant impact on the overall business.
