It is built of Bramley Fall stone; of which, in this erection alone, above 75,000 cubic feet were consumed.The Grand Junction Canal,  the Railways near neighbour for many miles, has changed little since it was opened at the beginning of the nineteenth century.South of the Hampstead Road, the fields and farm buildings of a great milk purveyor reached nearly to Seymour Street. And be it further enacted, That it shall be lawful for the said Company and they are hereby empowered to make and maintain a Railway, with all proper Works and Conveniences connected therewith, in the Line or Course, and upon, across, under, or over the Lands delineated on the Plan and described in the Book of Reference deposited with the respective Clerks of the Peace for the Counties of Middlesex, Hertford, Buckingham, Northampton, Warwick, and Worcester, the Liberty of Saint Alban, and the City of Coventry; that is to say commencing on the West Side of the High Road leading from London to Hampstead, at or near to the first Bridge Westward of the Lock on the Regent's Canal at Camden Town in the Parish of Saint Pancras in the County of Middlesex, and terminating at or near to certain Gardens called Novia Scotia Gardens, in the Parishes of Aston juxta Birmingham and Saint Martin Birmingham in the County of Warwick . Hence, the directors considered it prudent to avoid confrontation with the noble lord.
The Act authorising what became known as the Euston Extension received the Royal Assent in May 1835: an Act was passed in the Third Year of the Reign of His present Majesty, intituled An Act for making a Railway from London to Birmingham; and by the said Act several Persons were incorporated, by the Name and Style of The London and Birmingham Railway Company for carrying into execution the said Undertaking: And whereas it is expedient that the Line of the said Railway should be extended from its present Commencement near the Hampstead Road in the Parish of Saint Pancras in the County of Middlesex to a certain Place called Euston Grove, on the North Side of Drummond Street near Euston Square, in the same Parish and County . Passenger trains are to be moved on this portion of the railway, by a stationary engine in the Camden depot, and locomotive engines are to be employed on every other part of it.
They show its London terminus situated to the north of Hyde park, west of the Edgeware Road and adjacent to the confluence of the Grand Junction and Regents canals, an area of west London now known as Little Venice.
Stephensons second set of plans deposited two years later, show the London terminus located at a point slightly to the north of Battlebridge Basin on the Regents Canal and adjacent to the present day York Way, a name adopted in 1938 but at that time named Maiden Lane.
The outcome was that the Great Western Railway Act (1835) specified a terminus in the vicinity of todays Willesden Junction,  the intention being that the line would continue from this point over shared track to a terminus adjacent to that of the London and Birmingham Railway at Euston. And be it further enacted, That it shall not be lawful for the said Company to receive at their intended Station in Euston Grove, for the Purpose of Transport, or to deliver out therefrom, any Merchandise, Cattle, or Goods of any Description, save and except Passengers Luggage and small Parcels.
Sufficient land was therefore bought on which to construct four tracks into Euston and to accommodate both stations. At the London end of the line near Camden-town, the company have about thirty-three acres of land, intended as a depot for the buildings, engines, wagons, goods, and various accessories of the carrying department of the railway.