The head of a Dorset-based waste management company has been disqualified from being a director for seven years for failing to pay almost £1m in tax and allowing his company to dump toxic silt into a protected environmental area.

An Insolvency Service (IS) investigation found that from September 2008 to July 2010, while Peter Frampton was a director of Oil and Water Ltd (OWL), the company racked up £365,827 of VAT debt against which it made a single payment of just £69,116.

In addition, from April 2008 until July 2010 the company incurred PAYE and NIC debts of approximately £816,237, against which it made payments of just £356,415.

In 2007 OWL dumped silt that was highly contaminated with heavy metals and other toxins into the sea during the development of a yacht marina in Falmouth Harbour. The silt was completely unsuitable for disposal at sea as it threatened the marine environment and the food chain, including nearby oyster and mussel beds.

The company's actions were described by Natural England as the 'worst possible in terms of environmental impact,', and the Marine Management Organisation brought criminal proceedings against OWL for depositing material at sea without a licence under the Food and Environment Protection Act 1985.

OWL went into administration on 2 September 2010 owing at least £1.4m to its creditors, including just under £1m which was tax debt.

In February 2012 Frampton was convicted over the waste dumping, fined £25,000 and ordered to pay the prosecution's costs. He appealed against his conviction last year but was unsuccessful. Frampton has now given an undertaking he will not act as a director until March 2020.

Mark Bruce, a chief examiner at the IS Service, said: 'The substantial period of disqualification reflects the fact that where the actions of a particular company cause damage to the environment to such an extent that criminal prosecution by the relevant authority is deemed appropriate, the IS will take action to disqualify the directors.'