Why is Britain so Badly Governed? (In general not party specific)

While there is no single official running tally tracking politicians who specifically worked in hands-on industry or manual trades, detailed occupational analyses of the 650 MPs in the House of Commons show that fewer than 10% come from a manual, trade, or core industrial background, with only a tiny fraction having worked in heavy manufacturing, construction, or frontline production. 

The Rise of the Career Politician

Data compiled across successive general elections by the House of Commons Library and academic projects highlights a profound shift in where British politicians originate:

The "Never Worked Outside Politics" Group: Roughly 90 MPs (around 14% of Parliament) entered politics straight through the pipeline of party researcher, political advisor, special adviser (SpAd), or local councillor without holding a significant outside job. 
The Decline of Manual and Industrial Labour: In the post-war era (such as the 1945 Parliament), roughly one-third of Labour MPs were manual workers or ex-miners. By 2010, that proportion dropped below 10%, and estimates for recent parliaments suggest fewer than 10 to 15 MPs across the entire House of Commons previously held working-class manual or industrial trade roles. So how do politicians know what it is like on the shop-floor?
Dominant Professional Backgrounds: Over half of all MPs across major parties emerge from professional fields such as law, corporate business/finance, journalism, public relations, or charity management. So how do they know the day to day realities of running a company, be it large industrial conglomerate or a small family business?
Industry vs. Corporate Backgrounds
Distinctions are often drawn between corporate/financial management and actual "shop floor" or industrial trade experience:
While a moderate number of Conservative MPs have backgrounds in corporate management, consultancy, or small business ownership, very few possess long-term careers in traditional blue-collar industry, engineering production, or technical trades. 
Conversely, MPs with Labour or trade-linked backgrounds frequently spent their pre-parliamentary years as union officials, charity executives, or public sector workers rather than industrial labourers. 
As noted by consensus on various Reddit UK Politics Discussions, the modern recruitment pipeline for mainstream political parties heavily favours higher education, public policy, and media communications over practical experience in heavy industry or manual trades. 
In the immediate post-war era most politicians had been involved in doing things during the war. The great feat of the Normandy Landings was not done by a politician wishing it - the reality was hundreds/thousands of people doing detailed planning and organising things in minute detail. What, if anything, is done with the same care and attention to detail today.
My preferred solution of shooting the lot of them and starting again is not really practical or befitting a Permanent Deacon in the Catholic Church. But unless we have a radical reform of the way we select our politicians and the way political parties operate we will continue on our downward spiral whoever is in power.