Start with Only Time Will Tell, because there is no other option. The Clifton Chronicles are one serialised story split into seven volumes, not seven linked novels — there is no entry point except page one, and no volume resolves anything on its own.
The advice that actually helps, then, is not about order but about supply. Have The Sins of the Father in the house before you open book one. This is not a pacing suggestion: volume one does not end so much as stop, and finishing it with nothing to read next is the single most common complaint about the series. Every volume closes on a cliffhanger, deliberately, so pacing yourself between books is not really available to you.
Only Time Will Tell is around 400 pages of very fast, very plain prose. Archer writes short chapters with a hook at the end of each, and 60 to 80 pages an evening is entirely normal; most readers finish it in under a week.
What the series is about
Whether Harry Clifton is the son of a Bristol stevedore or of Hugo Barrington. That question is the engine of all seven books, and the rigid class boundary between the two families is what makes it consequential rather than merely dramatic. Archer tells it in rotating close third, each section headed with a character's name and a span of years, so the same events keep returning from new vantage points.
The core
The Sins of the Father, Best Kept Secret, Be Careful What You Wish For. Read these back to back — the second opens on the exact moment the first stopped, and the gap between volumes is where the series loses people.
This is Archer at his most assured. The stolen-identity plot and the New York murder trial play to his best register, which is courtroom and committee procedure; his years in Parliament and the Lords feed the institutional material directly and it shows in the accuracy. Best Kept Secret settles the parentage question institutionally, through a title vote, without settling it emotionally. Then Sebastian Clifton arrives as the second generation and the series widens from one family quarrel into a business and political saga, with a boardroom war and a saboteur replacing the trial.
The finish
Mightier than the Sword, Cometh the Hour, This Was a Man. Same pace — one volume a week if you have the evenings — and the last two should be read close together, because almost every thread converges in the sixth book and pays off in the seventh.
The story opens out beyond Britain here: an IRA bombing, a banned Russian novel, and Harry's campaign for an imprisoned dissident writer. Three strands run in parallel by book six, with Archer cutting between them at chapter length. This Was a Man closes four decades and finally answers the question asked on the first page of volume one, which only works because you read them in order — nearly every payoff was planted in a book that appeared years earlier.
Where to go next in Archer
One buying trap first. The record our catalogue holds is Prodigal Daughter; Kane and Abel, an omnibus pairing Kane and Abel with its sequel The Prodigal Daughter. Buy it and you have both, so do not also order Kane and Abel separately.
Read Kane and Abel first regardless of how the omnibus is titled. It is the compressed version of everything the Chronicles do across seven volumes — two men born the same day, sixty years, one long mutual destruction — and reading it afterwards is the pleasure, because you can see the same machinery running at a quarter of the length. The sequel then repeats the generational move in miniature.
Finish with Not a Penny More, Not a Penny Less, Archer's debut and his tightest construction: four men swindled by one conman, each recovering exactly his share. After seven volumes of saga it works as a corrective — no cliffhangers, no generations, one clean mechanism.
Where to stop
After This Was a Man you have the whole story and can stop with nothing missing. The two standalones are an appendix, not a continuation. If you want another multi-volume family sequence with a real ending, the Lymond Chronicles are the harder, better version of the same pleasure.
Follow the full ordered path here: The Clifton Chronicles Reading Order: Where to Start.