Iain Gilmour, 48, of George Street, Fratton, was spotted going through two red traffic lights in Manor Road, Buckland, on the evening of January 25.
Portsmouth Magistrates’ Court heard the senior teacher had drunk three bottles of wine and admitted having bought £200 of cocaine, a class A drug.
The Isambard Brunel Junior School headteacher admitted both possession of half a gram of cocaine, a class A drug, and drink-driving.
A breath test reading found he had 67 microgrammes of alcohol per 100 millilitres of blood. The limit is 35.
Visibly shaken in the dock, Gilmour said his actions had ‘destroyed’ his career but he has heeded the ‘wake-up call’ and is determined to save himself.
He said: ‘I admitted both offences as soon as I was charged and that up to now, I have had a clean record.
‘I still plead guilty to them but in doing so ask the court to understand that they were committed by a man who had been overwhelmed by his personal demons, a man who is still deeply ashamed of himself, but a man whose determination to turn his life around has been demonstrated by his actions over the last 14 days.’
He added: ‘I would like to publicly apologise to my family; the parents, children and staff at Brunel; this city where I have taught for 22 years, and finally the court.’
Gilmour said he had five years of depression and was ‘determined’ to succeed professionally and personally and thought he had ‘won both battles’ but was ‘incapable of rational thought’ on the night he was caught.
He said: ‘It turns out that these were Pyrrhic victories brought about the Trojan Horse of alcohol dependency entering my life.’
Gilmour added: ‘I was in such a state the night of my arrest when I compounded my stupidity by giving into a desire for something stronger.’
Sentencing, chairman of the magistrates’ bench, Lee Mandiwall said: ‘We feel for you, sir, but we’re here to uphold the law.’
Magistrates fined him £875 for each offence with an 18-month driving ban, plus £85 costs and £85 victim surcharge, totaling £1,920.
In a prepared speech Gilmour had told magistrates: ‘The last couple of years have been incredibly difficult for me.
‘As well as constant political and financial changes that all schools face, I have had to face further unique challenges as a headteacher.’
He told magistrates in July a long-serving colleague had died of cancer and telling the school was ‘hard enough’ but then had to argue to close the school to allow staff attend the funeral.
Prior to being arrested Gilmour had been placed on a ‘pre-capability support programme’ by the trust that runs the school as it ‘no longer had faith’ in his ability.
Magistrates heard how he met all targets on the course but had the programme extended.