"David Lloyd George was a force for good. We Welsh need to say this loudly and proudly. His astounding achievements are simply not recognised these days. The series we've produced for BBC Wales is meant to change that perception.

The 'Welsh Wizard' - raised in a cobbler's cottage in Llanystumdwy, near Criccieth - was a champion of the poor and disenfranchised. He was the founder of the Welfare State. Yes, that's right. Not Labour's 1945 government, with Nye Bevan and friends. What Bevan did was build impressively on the very solid foundations laid by Lloyd George.

But LG's political achievement was on a much higher plane. To establish Old Age Pensions and National Insurance was a great gift to the people of Britain. Standing up to the House of Lords, when they sought to block his reforms, was a monumental contribution to British democracy. We are still in his debt today.

And yet despite these reforms, and his brilliance as a statesman, the mention of his name (even in parts of Wales) can provoke a rather unattractive response. I have met Labour MPs who claim they can't stand LG. One Welsh member called him a 'sleazeball'. But this particular MP wasn't even aware of Lloyd George's main reforms.

Lloyd George was the man who, as Minister of Munitions, Minister for War and eventually Prime Minister, helped to lead Britain through The Great War, and whose courage strengthened the nation's resolve in its darkest hours. In its aftermath, he played an important role in encouraging world leaders to sign the Treaty of Versailles.

Yes, it's true that LG was a compulsive womaniser. Yes, it's true that he made a grotesque mistake in visiting Hitler before the Second World War. But must we let these facts hide his real achievements?

In making the series for BBC Wales - Lloyd George: The Peoples' Champion - I made a lot of discoveries which strengthened my conviction that this great politician deserves a much better reputation. We visited several places central to Lloyd George's life, and it was a particular treat for me to explore his childhood home in Llanystumdwy - Highgate.

It must always be remembered that this was the first British politician to rise from humble origins to Number 10 Downing Street. He never forgot what it was to be poor, and he had a burning desire to improve the lives of the working class people. His upbringing was crucial to the formulation and execution of his radical ideas later in life. And it was in Highgate that the currents of dissatisfaction running through the Wales of his day were discussed.

Although born in Manchester in 1863, David George (as he was then) was barely a year old when he was brought to Llanystumdwy. His mother Elizabeth decided to move her family back to her childhood home after David's father died at the age of 43.

Highgate is beautifully preserved. You get a really nice, warm sense of a family home, although it's not the sort of place you'd need to set aside an entire afternoon to explore. It has just two bedrooms, and five people slept in one of them: LG, his brother and sister, his mother and grandmother. In the other lived the man who had arguably more influence than any other on LG's early life - his uncle, the shoemaker Richard Lloyd.

Lloyd was well-read and had no time for the religious bigotry which, at that time, was one of the biggest issues dividing Wales. He encouraged the young David to familiarise himself with a wide range of ideas, and LG was helped by the large library left to him by his father. After adding Lloyd to his name in his uncle's honour, David developed a lasting sense of what was wrong with British society.

Which brings me to a celebrated incident in LG's life - later immortalised in an early feature film. I was lucky enough to view this rare footage on a visit to the National Library of Wales in Aberystwyth. Made in 1918 when LG was at the height of his fame, this film sheds light on that day, at Llanystumdwy school, when his willingness to combat surfaced for the first time.

Once a year, LG and his fellow pupils had to put on a special display of loyalty. They all had to recite the Anglican catechism to the local vicar and the local squire, even though many of the pupils were Nonconformists. Ten-year-old Lloyd George despised this little ritual, and he wanted to disrupt it. Led by David, the pupils refused to recite the catechism - and the film shows that LG's teacher might not have been unsympathetic.

Later, after he'd qualified as a solicitor, Lloyd George represented a family from Llanfrothen who wanted to bury their father - a Nonconformist - alongside his daughter in an Anglican churchyard. The vicar refused the request, and locked the gates to his graveyard. Outraged by the injustice and illegality of what had occurred - and, no doubt, spotting an opportunity to advance his own career - LG advised the family to break the padlock and bury the old man. They did as he suggested, and a famous court case ensued.

Lloyd George eventually won the case at the Court of Appeal with a brilliant performance and this helped to propel him on his parliamentary career.

It was a very slow start at Westminster! He spent 15 years as a backbencher, mostly because he was considered a trouble-maker, a 'cottage-bred' man unworthy of high office. There was also an early financial scandal involving goldmines in Patagonia, and the now infamous activity of his private life.

But opposing the Boer War soon made him famous and he was appointed to the cabinet in 1905 by the Liberal Prime Minister Henry Campbell-Bannerman. His popularity as President of the Board of Trade propelled him into Number 11 Downing Street, and he become Chancellor of the Exchequer in 1908.

This is when our journey took us to meet one of only two men who've held that post for longer than LG - Gordon Brown. I knew that he had a very high regard for his Liberal predecessor, so I arranged to meet for a brief chat. Brown spoke about him in glowing terms, paying particular attention to LG's 1929 document 'We Can Conquer Unemployment', which was roundly condemned at the time, but has since proved its worth.

The people who lined the streets and pathways of Llanystumdwy at his funeral in March 1945 knew about these achievements. As did the Americans in 1922 who greeted him as a true hero. You don't see many politicians enjoying a tickertape reception in New York these days.

So let's hear it for LG! Here was a man who helped shape modern Britain, and who made life immeasurably better for the vulnerable in our society. He's the greatest political leader Wales has produced, and it's time to say so very clearly."

WHAT OTHERS SAY ABOUT DAVID LLOYD GEORGE
"You have to recognise he was the grandfather of the Welfare State. Pensions, national insurance - a tremendous advance, far ahead of what the Americans have done even today. He would be so far to the left of New Labour today that he would be immediately expelled by Tony Blair!" Tony Benn

"People talk about Churchill as being a great Prime Minister but Lloyd George had an amazing ministerial and prime ministerial record, leaving behind major social change, which is something that Churchill did not have." Lord David Steel, former Liberal leader.

"To be able to create something from nothing, which was what was happening in the 1906-1914 liberal government, was a tremendous success and I don't think it will be surpassed by anybody. I think he was an incredible creative force." Chancellor Gordon Brown.

"It says in one of his diaries that it was a worthy aim to promote yourself by benefitting others and I think that is what drove him on - he was the peoples' champion." Dr William George (nephew of Lloyd George)