The M53 forms a spine road along the Wirral, beginning at the Wallasey (Kingsway) Tunnel under the Mersey and passing through the industrial areas of Ellesmere Port before reaching the Chester Bypass.
This is a road that turned out very differently to the original plan. The M53 was what became of a 1940s proposal to build a road running the length of the Wirral to link to new docks at Bidston Moss. By the 1960s, it had grown into a motorway linking Birkenhead's new tunnel with the A55 near Queensferry.
When it was finished as far as Bebington, it connected to the new M531 Ellesmere Port Bypass towards Chester, with the intention that it would become a spur of the M53 when the motorway was finished, even though for the time being it was a direct continuation. When it became clear that the M53 would never be extended any further, the M531 was absorbed into the M53. It was then extended south from the end of the Ellesmere Port Bypass to join the A55 east of Chester.
Between junctions 4 and 5, the carriageways split where the M53/M531 junction should have been. Driving through this part is very strange: it looks for all the world like a junction, and it's painfully clear that one road is turning into another, despite the continuous number. Until the early 2000s, there was even an unused flyover wide enough for a three-lane motorway standing across the northbound carriageway.
The Ellesmere Port Bypass section often feels like the little brother of the road to the north of there. In many ways it is. It was originally opened as an unclassified dual carriageway called the Hooton Industrial Road, intended to carry traffic to the motor plant and other heavy industry, before being hastily upgraded to carry the motorway. This is why it has such closely-spaced junctions and some surprisingly tight corners.
The M53 is also unusual in starting on a road with a number that's actually a name. At the northern end it flows directly into the Mersey Tunnel, whose road number is "(Tunnel)". This is confirmed by signs, which read "(Tunnel)" in yellow as if it were any other number. However, some early plans for the Kingsway Tunnel showed it as part of the M53, and even today the roadside marker posts are calibrated from a zero point at the Liverpool end of the tunnel, not from the start of the motorway in Wallasey.