Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Race | Date | Location | Pole Position | Fastest Lap | Race Winner | Constructor | Report |
| --- | --- | --- | --- | --- | --- | --- | --- |
| South African Grand Prix | 23 January | Kyalami | René Arnoux | Alain Prost | Alain Prost | Renault | Report |
| Brazilian Grand Prix | 21 March | Jacarepaguá | Alain Prost | Alain Prost | Alain Prost | Renault | Report |
| United States Grand Prix West | 4 April | Long Beach | Andrea de Cesaris | Niki Lauda | Niki Lauda | McLaren - Ford | Report |
| San Marino Grand Prix | 25 April | Imola | René Arnoux | Didier Pironi | Didier Pironi | Ferrari | Report |
| Belgian Grand Prix | 9 May | Zolder | Alain Prost | John Watson | John Watson | McLaren - Ford | Report |
| Monaco Grand Prix | 23 May | Monaco | René Arnoux | Riccardo Patrese | Riccardo Patrese | Brabham - Ford | Report |
| Detroit Grand Prix | 6 June | Detroit | Alain Prost | Alain Prost | John Watson | McLaren - Ford | Report |
| Canadian Grand Prix | 13 June | Circuit Gilles Villeneuve | Didier Pironi | Didier Pironi | Nelson Piquet | Brabham - BMW | Report |
| Dutch Grand Prix | 3 July | Zandvoort | René Arnoux | Derek Warwick | Didier Pironi | Ferrari | Report |
| British Grand Prix | 18 July | Brands Hatch | Keke Rosberg | Brian Henton | Niki Lauda | McLaren - Ford | Report |
| French Grand Prix | 25 July | Paul Ricard | René Arnoux | Riccardo Patrese | René Arnoux | Renault | Report |
| German Grand Prix | 8 August | Hockenheimring | Didier Pironi | Nelson Piquet | Patrick Tambay | Ferrari | Report |
| Austrian Grand Prix | 15 August | Österreichring | Nelson Piquet | Nelson Piquet | Elio de Angelis | Lotus - Ford | Report |
| Swiss Grand Prix | 29 August | Dijon | Alain Prost | Alain Prost | Keke Rosberg | Williams - Ford | Report |
| Italian Grand Prix | 12 September | Monza | Mario Andretti | René Arnoux | René Arnoux | Renault | Report |
| Caesars Palace Grand Prix | 25 September | Caesars Palace | Alain Prost | Michele Alboreto | Michele Alboreto | Tyrrell - Ford | Report |
Question:
When were the British Grand Prix races?
Answer:
18 July