Labour declared £2,829,146 in private donations in the same period, while the Lib Dems registered £2,916,505. The SNP declared £130,738 - the majority of which came from one single donation.
The figures, which are released on a quarterly basis by the Electoral Commission, include only those given above a threshold of £7,500 - all parties are likely to have received multiple donations below that figure.
In total, 15 political parties registered in Great Britain reported over £19m in donations and public funds in the third quarter.
The biggest single gift to the Tories in that week was £1.5m from theatre producer and regular donor John Gore.
Louise Edwards, Director of Regulation at the Electoral Commission, said: “Publishing data about party donations and loans on our online database means voters can clearly see where political parties receive their funds from. This leads to a more trusted and transparent political finance system and helps ensure compliance.
“Where parties fail to deliver their return on time, and there is no reasonable explanation for such a failure, we will take a robust approach in dealing with this in line with our Enforcement Policy.”