RM4

This road is number 4 in 'Roman Roads of Britain' by Ivan D Margary. It runs from London to Exeter.

Section 4a of this route is called The Devil's Highway, and runs from London to Silchester, the site of the Roman town Calleva Atrebatum. Here section 4b continues to Old Sarum on the outskirts of Salisbury, passing through modern day Andover. This section is called the Portway.

Section 4c continues on a definite line from Salisbury to Badbury Rings. From here, a spur, section 4d, goes down to Hamworthy, the site of the modern port of Poole. Clearly this was a Roman Port!

Section 4e runs from Badbury Rings to Dorchester. Most of this section is a collection of footpaths, bridleways and fields.

Section 4f runs from Dorchester to Exeter, via Bridport and Honiton. However, the line of this road around Bridport doesn't appear on modern OS maps, and isn't at all obvious.

Devil's Highway

RM4, The Devil's Highway starts at Newgate, at the edge of the City of London, corresponding to the roman town Londinium. Incidentally St Paul's Cathedral is virtually at the start of the road. Also off note, we're about 100 metres south of the London end of the A1. From here we head west, the modern A40 following our course. There is a brief deviation in Holborn where the A40 has a one way system, New Oxford St follows the line. We reach Marble Arch, and now are on the A402 on the north side of Hyde Park. We follow this road past Shephard's Bush, then become the B409. Here we reach Turnham Green tube station, and the line of the roman road becomes briefly unnavigable, subsumed underneath tube lines. We are joined by the A315 just the other side of the lines, and almost immediately reach the Chiswick Roundabout. Here, we have a brief multiplex with the A205 South Circular, and then the A315 continues on the Roman route.

The A315 now enters Brentford. There's a kink in the road where we briefly deviate from the roman line, for no apparent reason. Now we reach Hounslow, and the roman road continues up the now semi-pedestrianised High Street. From here the A315 follows the Roman road all the way to Clockhouse Roundabout. We're now on the A30 until we reach Staines. Here, the A308 follows the line breifly, with another pedestrianised High Street, and then we cross the Thames.

From here the line of the road briefly becomes hard to trace, but reappears in Sunningdale, just north of, and parallel to, the modern A30. As we cross the A322, the road turns from heading West-Southwest to heading nearly due West across Bracknell Forest. The road here is occassionally followed by footpaths, bridleways, byways, and, very occassionally, a minor road. On reaching Riseley, the rights of way become more consistent, with minor deviations, all the way to Slichester, the roman town of Calleva Atrebatum.

Portway

The Portway follows an impressively straight line Southwest from Silchester to Salisbury. However, apart from the brief bridleway, there is no public right of way along the line of the roman road until south of Kingsclere. Here, we're joined by the by Meadham Lane, which is the U33, and then we're briefly joined by the C67 for half a mile. The road is then followed by a bridleway for the 2.8 miles to the C67 again, now the old A34 (the newer road runs alongside just to the west).

The road continues across fields, until we reach St Mary Bourne. Briefly a footpath, we become a proper road again, the C99. This takes us all the way to Andover. The road is now impossible to follow as it gets subsumed in suburbia. However, we reemerge at the Hundred Acre Interchange, where we cross the A303, and follow the C43, although the line isn't followed perfectly. Now at Grateley, the road again becomes a bridleway. This runs beside the West of England line, just the other side of which lies the Porton Down danger area. Along here we enter Wiltshire. The bridleway then enters the village of Porton itself. After a brief bit of the road without a public right of way, we meet a roundabout with the A338, and make a beeline to Old Sarum.

Ackling Duke

The next section of RM4 is called Ackling Dyke. This continues the same general direction as the Portway, heading from Old Sarum to Badbury Rings, near Wimborne. After the occassional suburban road in Salisbury, we cross a few fields and the River Nadder. We cross the A3094 and now there is a footpath to Old Shaston Drove. The road is now mostly bridleway to Woodyates, where we meet the A354. The A354 then turns away, and we continue in a straight bridleway. We then get a brief section of road at Witchampton, before we get a final bridleway to Badbury Rings.

Hamworthy Spur

This spur connects Badbury Rings to the port of Hamworthy. After crossing the Kingston Lacy estate, we pass the outskirts of Wimborne until we reach the Lake Gates Roundabout. Here we briefly follow the line of the C5, but then become a bridleway down the boundary between Corfe Mullen, Dorset, and Broadstone, Poole. We reach the Upton Park Junction, where we go under the A35 and enter Upton Country Park. The road continues in a straight line into Hamworthy, whereas the bridleway eventually deviates to meet the B3068.

Badbury to Dorchester

This section of RM4 doesn't have a definitive name, let us refer to it as RM4e. However, it continues the line of the Portway. From Badbury Rings we have a brief bridleway, and then there's New Rd into Shapwick (this is a D road). We then have to cross fields and the River Stour, until we reach a bridleway and enter Winterborne Kingston. After this, again there is no public right of way, until we approach Tolpuddle, but we then hit the A35. The road then again crosses fields to Puddletown Forest, a popular mountain biking site. After a few more fields, we reach Kingston Maurward and the Stinsford Roundabout. We then follow the B3150 (old A35) into central Dorchester.

Dorchester to Exeter

Again without a definitive name, RM4f is also one of the harder Roman Roads to track. It starts simply enough, as we leave Dorchester on the B3150 and pass through Poundbury to Monkeys Jump Roundabout, then the A35 carries on in a straight line. We then leave the A35 for the aptly named Roman Road. This then follows the ridge onto Eggardon Hill. However here the line gets messy, as this (public domain) excerpt from Roman Roads in Britain by Thomas Codrington shows:

From near Eggardun the road turns towards the south-west and slants down the hill by Spyway Green, and is traceable through the arable land. When the old road was broken up it was seen to be "composed of a bed of large flints laid on the substratum of chalk, with a thick layer of smaller stones on the top, the whole almost as compact as a wall."​29 According to Davidson, the course of the road is joined by the present road to Bridport about a mile and a quarter west of Askerswell; but there is a good deal in favour of the course given by Warne on the authority of a local antiquary, through Up Loders and Yondover and along the road from Yondover to the main road one mile east of Bridport. From that point parish boundaries follow the present road to Bridport, and it appears to be on the line of the Roman road through Bridport, and on to half-a‑mile beyond Chideock, where the Roman road mounted Chardown Hill, and passed over Stonebarrow Hill, the course being by Cold Harbour and along a lane followed by a parish boundary for two miles on to the river Char. At Charmouth the Roman road seems to have divided, one branch continuing along the coast, and the other going by Axminster and Honiton.

Since this was written the A35 has been bypassed, with the B3162 following the roman line through Bridport. We continue following the general route of the A35 to Honiton, where we now follow the old route of the A30 to Exeter - parts of which are now the B3177 and B3174.