Small private companies with a year end of 30 June 2015 and into their second or later year of existence should submit their accounts to Companies House by 31 March 2016 in order to avoid a Late Filing Penalty.
Any corporation tax for small companies with a 30 June 2015 year end is due to be paid on 1 April 2016 in order to avoid Late Payment Interest, which is currently charged at 3%.
New small private companies in their first year of existence have a deadline which is usually slightly shorter than this unless they have changed their year end, in which case it may be considerably shorter. They can look on the Companies House website to determine their deadline, but their accountant may have warned them already.
If you miss this deadline then we advise you to get your accounts drawn up and submitted as soon as possible in order to avoid further penalties. The need to be able to produce a set of accounts at high speed is one of our motives in taking an interest in new technology.
If you are over the deadline, there may be other problems such as with s455 tax and P11D returns. We can only point out that leaving things to the last minute and beyond can often turn out to be expensive.