Enfield was possibly the most popular comedian in the UK at the time. His comedy show was a series of sketches that lampooned the UK way of life, and captured the psyche of the nation with characters like Stavros the kebab shop owner, and the Scousers who were typical northerner stereotypes.

The UK at the time was going through some severe changes as Margaret Thacher rebalanced the economy from manufacturing to services, which led to a split in the country between the prosperous south and the grim north. Thatcher pursued a policy of monetarism, which left up to 3 million people, mainly in the north, long term unemployed. The heavy industry such as mining, manufacturing and shipbuilding industries vastly reduced in size under her leadership.

Other changes included selling off the council housing stock. People could buy their council houses at up to 50% off, and flats were even cheaper at 70% off if you'd lived there long enough. Even people in council properties for three years could get a third discount on their value. Move into a council house in London worth £100k, three years later you could buy for £66k and have £33k on tap from the bank to play with. Homes were more expensive in the south, and since that's where the well-paying finance and banking jobs were, people took advantage and were left with a lot of equity in their homes, which many used to fund holidays and luxury cars..or even swap straight up into larger homes. So one half of the country was basically swimming in money while the other half struggled.

Credit and purchasing schemes were easier to access as Thatcher loosened the regulations on banking. The expansion of the city of London required nearly half a million more workers, meaning that banking and finance were no longer the preserve of Oxbridge and the old boy network, now anyone had a shot. People whose fathers used to be day labourers at the docks now earned six-figure salaries and bonuses in the city.

Enfield took that situation and ran with it using characters like Loadsamoney and considerably richer than you sketches. Loadsamoney portrayed the typical stereotype of an ordinary southerner who'd had gained Thatcher's instant wealth. It was a similar time to the Reagan "greed is good" years in the US.

As the show was so popular, these characters became a symbol of the time, and football teams from London used to wave bundles of banknotes at supporters of teams from the north of the country like Newcastle. British people are usually rather restrained when talking about money. Enfield and Loadsamoney perfectly captured the Zeitgeist of the time and the newly wealthy that wanted to scream and shout about how much they earned and the new possessions it brought.

I've posted it higher, but this link is a good overall summary of the good and bad of Thatcher's economic policies. The split in the election map of the UK today and the deep division is still felt

Firstly it was 1988, not 1984. I'm not quite sure what you're asking. It's a comedy novelty song, which always silly and bizarre, and are neither unique to the UK nor to the 1980s. e.g. this is from 1966 and also got to number 4 in the U.K. and number 3 in the US:

https://www.youtube.com/watch?v=3Fn36l_z3WY

If you're asking how Harry Enfield became so popular, it's because he performed his character on Saturday Live, which was a Channel 4 programme designed to showcase the burgeoning "alternative comedy" scene in the UK, taking its lead from shows such as "The Young Ones". "Saturday Live" also took inspiration from NBC's Saturday Night Live in the US and launched the careers of Stephen Fry and Hugh Laurie, Hale and Pace, Harry Enfield and Paul Whitehouse, Lee Evans, Jo Brand and Julian Clarey as well as starring alternative favourites like Ben Elton, French and Saunders, Rik Mayall and Adrian Edmonson.

Alternative comedy born out of the Comedy Store in London and was, at heart:

• 1. a reaction against old school comedians who were mocked and derided for their outdated, racist and sexist jokes (e.g. Jim Davidson, Bernard Manning etc.)
• 2. A more experimental style of comedy which would deliberately subvert traditional forms, sometimes taking inspiration from the Theatre of the Absurd, surrealism and dadaism.
• 3. an overtly political reaction against the Thatcher government and right-wing politics.

So you had in alternative comedy, a counter-cultural movement with a clear punk ethos which despised the current government.

Harry Enfield's Loadsamoney, written by Charlie Higson and Paul Whitehouse, was always intended as a satire of 1980s greed and materialism, often summed up by Margaret Thatcher's famous quote "there's no such thing as society"

Full quote:

They are casting their problems at society. And, you know, there's no such thing as society. There are individual men and women and there are families. And no government can do anything except through people, and people must look after themselves first. It is our duty to look after ourselves and then, also, to look after our neighbours.

It became popular because it fitted the zeitgeist.

In Thatcher and Thatcherism (1997) Eric Evans argued that Loadsamoney became one of the three dominant symbols of materialist Britain in the later 1980s (alongside yuppies and privatisation). While yuppies were middle class, Loadsamoney was distinctly working-class. In modern parlance he would be described as a 'chav' being socially crass and vulgar. The type persists today with 'bling' lifestyle reality shows like "The Only Way is Essex". Loadsamoney satirised and epitomised a kind of nightmarish hate figure of both the left and right.

Once firmly established in the national consciousness, Labour leader Neil Kinnock first used the term in a critique of late Thatcherite economics on 20th May 1988 (The same week the song reached number 4). His speech at a party meeting in Wales criticised Margaret Thatcher and her Chancellor Nigel Lawson for creating a 'Loadsamoney economy'. The Daily Express commented the next day that a loadsamoney economy was evidence of her success rather than failure. The Sun said 'Better a loadsamoney economy than a loadsadebt economy.' Thatcher though ultimately disassociated herself from the term saying at the Conservative Party Conference on 14th October 1988:

We are told that all we care about is 'Loadsamoney'. Because we give people the chance to better themselves, they accuse us of encouraging selfishness and greed. What nonsense. Does someone's natural desire to do well for himself, to build a better life for his family and provide opportunities for his children, does all this make him a materialist? Of course it doesn't.