Since the majority of companies use some form of computer software to handle their bookkeeping, it's only sensible that there should be a way of actually filing the forms electronically too. And there is.
Software carrying the logo of the HM Revenue & Customs Payroll Standard has been tested by the HMRC. It means that the package incorporates all the essential features for calculating tax, salaries, National Insurance contributions and so on.
Using a piece of software that carries this logo means that you will be able to file the relevant end-of-year tax details electronically rather than having to complete them all by hand. A list of accredited software products can be found here
There's also a Pensioner Payroll Standard service available. This product signifies to pension payers that your service is up to date, and you can calculate PAYE and returns online as well as a range of payroll functions. More information about this can be found here.
Doing your bookkeeping electronically makes sense if you have the necessary equipment, but be sure to make regular backups of all your accounts data. Preferably these backups should be kept off-site, so that if anything should happen to the originals (theft, fire, viruses, etc.), the backups won't be affected