In 1846 Francis Rufford, the Chairman of the OW&WR saw that the inflation of construction costs brought about by the Railway Mania, now at its height, meant that the £1.5 million estimate they had used would be inadequate, and he asked the GWR to increase its rent in proportion to the anticipated cost, thought to be £2.5 million at least. The GWR was not immediately opposed to this, and the OW&WR may have understood that the GWR had formally agreed. The OW&WR Board improperly represented to prospective shareholders that the GWR guaranteed 4% interest on the whole construction cost whatever that might prove to be, and this led to soured relations between the two companies for a long period later on. (In August 1847 when the OW&WR found itself once again embarrassed financially, it asked the GWR to raise the interest rate to 5%, increasing the bad feeling.)