the thin end of the wedge

the thin end of the wedge

The inconspicuous beginning or initial stage of something that will be unfavorable, cause problems, or bring decline. Primarily heard in UK, Australia. This law is the thin edge of the wedge. If it's passed, you can expect more extreme legislation to follow.
See also: end, of, thin, wedge
Farlex Dictionary of Idioms.

the thin end of the wedge

BRITISH
The thin end of the wedge is the beginning of something bad which seems harmless or unimportant at present but is likely to become much worse in the future. I think it's the thin end of the wedge when you have armed police permanently on patrol round a city. This decision could prove to be the thin end of the wedge towards making the 1.68 inch ball the legal ball the world over.
See also: end, of, thin, wedge
Collins COBUILD Idioms Dictionary, 3rd ed.

the thin end of the wedge

an action or procedure of little importance in itself, but which is likely to lead to more serious developments. informal
See also: end, of, thin, wedge
Farlex Partner Idioms Dictionary

the thin ˌend of the ˈwedge

(especially British English) used for saying that you fear that one small request, order, action, etc. is only the beginning of something larger and more serious or harmful: The government says it only wants to privatize one or two railway lines, but I think it’s the thin end of the wedge. They’ll all be privatized soon.
A wedge is a piece of wood, metal, etc. with one thick end and one thin pointed end that you use to keep two things apart or to split wood or rock.
See also: end, of, thin, wedge
Farlex Partner Idioms Dictionary
See also:
  • in a cleft stick
  • candy-coat
  • slip past (someone or something)
  • sneak up to
  • sneak up to (someone or something)
  • slip (something) to (one)
  • slip across
  • prejudice (one) against (someone or something)
  • prejudice against
  • exit stage left
References in periodicals archive
The latest attack on pension rights is the thin end of the wedge. Email your MP now.
Whatever happened to the silly season?
And residents are again celebrating after a scaled down plan for just one detached home - which some campaigners suspected would be 'the thin end of the wedge - was rejected by Rochdale council.
Residents' joy at rejection of home plan
The disallowance of free TV licences for the elderly is the thin end of the wedge. What next I ask myself - the end of bus passes, fuel allowance, prescriptions, Christmas bonus - all these adding up to, I reckon some PS1.25 per day per elderly person!
What will be taken next?
The MP said in a tweet that he had visited a DRC to see it for himself and called them "the thin end of the wedge".
MP in row over views on 'shooting galleries' DRUGS
"We believe it is the thin end of the wedge for the introduction of universal metered domestic water charges in future.
80,000 homes to face [euro]260 'excessive water use'charges; Fear on cost to households; Government plan slammed
"Is it the thin end of the wedge?" SFRS director Lewis Ramsay said: "Retained firefighters were requested to cover unplanned absence, such as sickness, within some wholetime stations in our East Service Delivery Area.
PART-TIMERS PERIL; Firefighters slam staff shortages
"Shotts have been on the thin end of the wedge for years."
Leisure Centre is saved .... for now
And Black Country Labour MP John Spellar (Lab) said: "This must not be the thin end of the wedge."
May facing opposition over vote for prisoners
"What we are seeing here is the thin end of the wedge.
The winter fuel cut is thin end of the wedge
However, this is not the thin end of the wedge. If a little of the moor needs to be given up for the good of the city, then so be it.
The road ahead
As far as I can see this will be the thin end of the wedge, as if these houses are built and people move in, the next thing will be house owners cannot stand the planes coming and going, leading to cutting flights further hence making the airport a none viable thing to run, leading to its closure.
I HEAR Durham Tees [...]
However, would it be the thin end of the wedge, paving the way for the abolition of traffic from the city centre permanently?
YOU SAY
This Bill is the thin end of the wedge, allowing doctors to prescribe a lethal drug to dying patients who request it.
The right to die becomes [...]
If the promised law appears to be limited in scope at the outset we can be sure this would be the thin end of the wedge, with all workers eventually brought within its remit.
Strike clampdown is attacking democracy; LETTERS