Missing historical data and reconstructing accounts-obligations re records

A business has been left "stuck" at the moment as a former employee who had complete control of financial matters and reporting etc has just left without leaving data backups, detailed paperwork etc of the accounts for the Ltd company.

The accountants who worked with this employee are advising that they have no other papers (they produced a set of basic accounts that have been filed), but say they worked from data supplied by the employee -and they have nothing at their premises.(so I have no P&L either).

The ex-employee has been approached but he too advises that he has nothing that he can hand back. He has handed back credit cards and keys etc.

Can anyone advise me what the accountants are legally responsible to provide to this ltd company?  Without a full detailed P&L, how can i reconstruct the accounts without opening balances?

There was an outstanding invoice that was being disputed between the accountant and ltd company and so neither side were being too progressive about this- but regardless should the accountants firm have a copy of the detailed P&L and some back ups of the data that was provided..or is this not applicable now that "web" accounting is here?

Any advice about the way forward would be good as I am really keen to see this business thriving again. It is fair to say that accounting/reporting matters are not the directors forte.  He is good at what he is in business for !

thanks.