A new Hawk announced in May 1957 had a completely new body with unitary construction which it would go on to share with the 1958 Humber Super Snipe.
The new model was, like its predecessors, a large car.
For the first time an estate variant was available from the factory - the Hawk estate had the largest unitary bodyshell of any British-built car up to that point, a status it retained until the Jaguar Mark X was launched in 1961.
The 2267 cc engine was carried over, though with modifications to the distributor mounting, and other details; and an automatic transmission, the Borg Warner D.G. model, was now available.
The body was styled in Rootes' own studios and featured more glass than previous models, with wrap-around front windscreen, which gave it a considerable resemblance to a base model 1955 Chevrolet 4-door sedan.
The missing rear quarter-lights were returned in Series IV.
The estate version featured a horizontally split tailgate—the lower half opening downwards (to provide an extra length of luggage-platform if necessary) and the upper half upwards.
The fuel-filler cap was concealed behind the offside rear reflector.

There were several revisions during the car's life, each resulting in a new Series number.

The 1959 Series 1A had changed gear ratios and minor trim changes.

The Series II launched in October 1960 had disc front brakes, servo-assisted.
The automatic option was no longer available on the home market.

The Series III of September 1962 had a larger fuel tank and bigger rear window.
The export model automatic option was also dropped.

More significant changes came with the October 1964 Series IV.
The roof was made flatter, the rear window smaller and an extra side window fitted behind the rear doors.
Synchromesh was fitted to bottom gear.
An anti-roll bar was fitted at the rear.

The final Series IVA of 1965 saw the automatic option re-introduced, this time being the Borg Warner Model 35.

Some "Series" cars are found with a floor-type gear change replacing the (good quality) standard column-mounted gearstick — these are later owner modifications resembling the original factory option, and the parts necessary for this were obtained from the Commer Karrier Walk-thru–type vans and light lorries which were also made by the Rootes Group at this time.
All of the automatic transmission–optioned cars were fitted with the column-type selectors only.

A Series I car without overdrive was tested by the British The Motor magazine in 1957 had a top speed of 83.9 mph (135.0 km/h) and could accelerate from 0-60 mph (97 km/h) in 19.7 seconds.
A fuel consumption of 22.5 miles per imperial gallon (12.6 l/100 km; 18.7 mpg‑US) was recorded.
The test car cost £1261, including taxes of £421.

In March 1967 Rootes announced that production of the Humber Hawk, along with that of the Super Snipe and Imperial had ceased.
 The announcement stated that the cars' place in their range would be filled by Chrysler Valiants imported from Australia.

After Hawk production ended, Rootes came to concentrate on sectors offering greater volume, no longer featuring as a UK provider of large family cars.
It had, in particular, been unusual for UK manufactured cars of this size to feature a spacious station wagon / estate car version; and, following the demise of the Humber Hawk, the UK market for large estate cars quickly came to be dominated by the Volvo 145, introduced to the UK in March 1968,  and its successors.
A new Hawk announced in May 1957 had a completely new body with unitary construction which it would go on to share with the 1958 Humber Super Snipe. The new model was, like its predecessors, a large car. For the first time an estate variant was available from the factory - the Hawk estate had the largest unitary bodyshell of any British-built car up to that point, a status it retained until the Jaguar Mark X was launched in 1961. The 2267 cc engine was carried over, though with modifications to the distributor mounting, and other details; and an automatic transmission, the Borg Warner D.G. model, was now available. The body was styled in Rootes' own studios and featured more glass than previous models, with wrap-around front windscreen, which gave it a considerable resemblance to a base model 1955 Chevrolet 4-door sedan. The missing rear quarter-lights were returned in Series IV. The estate version featured a horizontally split tailgate—the lower half opening downwards (to provide an extra length of luggage-platform if necessary) and the upper half upwards. The fuel-filler cap was concealed behind the offside rear reflector.
There were several revisions during the car's life, each resulting in a new Series number.
The 1959 Series 1A had changed gear ratios and minor trim changes.
The Series II launched in October 1960 had disc front brakes, servo-assisted. The automatic option was no longer available on the home market.
The Series III of September 1962 had a larger fuel tank and bigger rear window. The export model automatic option was also dropped.
More significant changes came with the October 1964 Series IV. The roof was made flatter, the rear window smaller and an extra side window fitted behind the rear doors. Synchromesh was fitted to bottom gear. An anti-roll bar was fitted at the rear.
The final Series IVA of 1965 saw the automatic option re-introduced, this time being the Borg Warner Model 35.
Some "Series" cars are found with a floor-type gear change replacing the (good quality) standard column-mounted gearstick — these are later owner modifications resembling the original factory option, and the parts necessary for this were obtained from the Commer Karrier Walk-thru–type vans and light lorries which were also made by the Rootes Group at this time. All of the automatic transmission–optioned cars were fitted with the column-type selectors only.
A Series I car without overdrive was tested by the British The Motor magazine in 1957 had a top speed of 83.9 mph (135.0 km/h) and could accelerate from 0-60 mph (97 km/h) in 19.7 seconds. A fuel consumption of 22.5 miles per imperial gallon (12.6 l/100 km; 18.7 mpg‑US) was recorded. The test car cost £1261, including taxes of £421.
In March 1967 Rootes announced that production of the Humber Hawk, along with that of the Super Snipe and Imperial had ceased.  The announcement stated that the cars' place in their range would be filled by Chrysler Valiants imported from Australia.
After Hawk production ended, Rootes came to concentrate on sectors offering greater volume, no longer featuring as a UK provider of large family cars. It had, in particular, been unusual for UK manufactured cars of this size to feature a spacious station wagon / estate car version; and, following the demise of the Humber Hawk, the UK market for large estate cars quickly came to be dominated by the Volvo 145, introduced to the UK in March 1968,  and its successors.
Humber Hawk