ACCOUNTANTS tend to love the idea of filing their client's tax returns online. The only trouble is that they distrust the system.

That is the complaint made by Gail Monnickendam, president of the West Yorkshire Society of Chartered Accountants, which covers York and North Yorkshire - and it comes as the 2007 tax deadline of January 31 for self-assessment returns looms.

It will be a crucial test of the HM Revenue & Customs' (HMRC) enthusiastically-welcomed FBI (Filing By Internet) system. It will be followed soon afterwards by the May 19 deadline for Pay-As-You-Earn submissions - "and it will be critical in terms of building confidence, " she says.

Gail, commercial director of Harrogate and Pudsey-based property and developers Lunn Ventures Group Ltd, believes that the lack of confidence in the system "is deterring tax professionals from recommending that they use it."

Her fears are confirmed by a survey of 1,000 of the UK's leading accounting bodies, including the Institute of Chartered Accountants in England and Wales (ICAEW).

Conducted by the Working Together E-Group, the research found that in spite of widespread support for e-filing, there are "significant concerns" about HMRC's track record for delivering reliable, robust systems with sufficient capacity to perform at peak times.

More than half (54 per cent) questioned had already filed more than 75 per cent of income tax returns electronically - highlighting the popularity of the scheme - but also revealing the extent to which it is under used and the glitches that can await. For instance: . Overload at the last minute may mean not being able to get on to the system during office hours. Result?

Individuals or their accountants will have to file at odd and antisocial hours to guarantee that the returns get in on time . Expect self-employed returns with more than one accounting period ending in the year to be rejected . Don't even think about submitting partnership returns. HMRC software simply is not equipped to accept them . You are doomed if you've amassed huge share options. Too many digits cause submission failure . Multiple Capital Gains computations? Forget it . Don't have more than seven beneficiaries in a trust. The software can't take it . Nothing wrong in trying to carry forward capital gains losses on the Capital Gains page by showing that current year gains were less than the annual exemption. But unless one of the capital gains boxes is completed then the return will be rejected . If your business has an address with more than five lines, the system cannot cope . If you have too many capital gains in one year for the available space, switch off and start again - on a manual return.

The report concludes: "Too many selfassessment returns submitted using FBI are rejected and many of the reasons for rejection are unacceptable in a system that has been in existence for five years."

So when are your tax return deadlines in 2007? And what are the penalties for delay? Here's a reminder.

January 31 for self-assessment returns. If you were sent a tax return by October 31 last year that is the date at which your 2005/06 tax return should be in. If not, you will be automatically charged £100 penalty.

This is also the deadline for paying the balance of any tax you owe (the balancing payment). Until HMRC receives your balancing payment it will charge you daily interest.

This date is also the deadline for making any first "payment on account" for the current tax year, that is 2006/07.

February 28 - still no balancing payment made? Expect a five per cent surcharge on top of the amount you owe.

April 6 - start of the new tax year.

A tax return, or notice to complete a tax return will be sent out to all who meet the criteria.