The M1 and the A1 both run north from London, and they finally join east of Leeds. If one is closed or badly held up, the other is often the way round. This page lists the roads that link them, south to north, with the junction at each end.

A1 or A1(M)? It changes along the way

Only four lengths of the A1 are motorway: junctions 1 to 10 (South Mimms to Stotfold), 14 to 17 (Alconbury to Peterborough), 34 to 38 (the Doncaster bypass) and 40 to 65 (Darrington to Washington). Stamford, Wansford, Grantham, the Black Cat, Brampton, Apleyhead and Markham Moor are all on the plain A1, which has no motorway junction numbers.

The crossings, south to north

Link road	M1 end	A1 end
A1 Great North Way	J2 (southbound exit, northbound entry only)	Fiveways Corner, plain A1
M25	J6A = M25 J21A (part junction)	M25 J23 = A1(M) J1, South Mimms (part junction)
A414	J7 and J8	A1(M) J3 and J4, Hatfield
A505 via Luton	Luton (J10 and J11)	A1(M) J9
A421	J13	Black Cat, plain A1
A428	J18	Plain A1, south of St Neots
A43 via Kettering and Corby	J15A	Stamford, plain A1
A14	J19	Brampton, plain A1
A47	No M1 junction	Wansford, plain A1
A52	J25	Barrowby near Grantham, plain A1
A57	J31	Apleyhead, plain A1 (shares it to Markham Moor)
M18	J32	A1(M) J35
M62	J42	A1(M) at Ferrybridge
The merge	J48, where the M1 ends	A1(M) J43, near Micklefield

Worth knowing before you rely on one

• Part junctions. M1 J2, M1 J6A and M25 J23 do not allow every movement. Check the signs before committing.
• The A45 is not a link. It leaves Northampton eastwards but ends on the A14 at Thrapston and never reaches the A1.
• The A14 now meets the plain A1 at Brampton, not the A1(M). The old line to Alconbury is now the A1307, although A1(M) junction 14 is still signed “A1 to A14”.
• The A47 has no M1 junction. From the A1(M), junction 17 is signed for it via the A1139.
• The Black Cat roundabout, where the A421 meets the A1, is being rebuilt as a three-level junction due in spring 2027.
• The M18 is the first motorway-to-motorway link north of the M25, and runs on to the M180 and M62.
• At the merge, northbound M1 traffic heading for the A1(M) south must leave at M1 junction 47 and use the A642.

Where to find the news for each road

The A1(M) has its own site, A1M Traffic, launching now, and it carries the same guide from the A1 side: A1(M) and M1 link roads. The M25 has M25 Traffic. For the A-roads above and for the M18 and M62, see Traffic News England. The M1 itself is on our latest M1 traffic news page.