Flu cases have soared more than two and a half times in just a fortnight - fuelled by the deadly 'Aussie' bug, according to new research.
About 31,300 patients in England visited their GP last week - a rise of almost 153 per cent since the start of the year.
The virus is affecting older patients aged 65 and over most, with rates moving into the "very high threshold".
The most prevalent strain is influenza B which includes H3N2, or 'Aussie flu' which claimed the life of Bethany Walker, from Applecross in the Scottish Highlands, earlier this month.
Professor Helen Stokes-Lampard, Chair of the Royal College of GPs (RCGP), said: "General practice continues to face huge winter pressures with a significant increase in patients presenting with influenza, and high numbers of patients continuing to present with other common winter illnesses."
Last week Public Health England revealed flu fatalities soared by 77 per cent in just seven days in England as fears grow of the worst outbreak in 50 years.
Its figures showed 93 people had lost their lives to flu this winter - 85 in England and eight in Scotland.
The crisis is adding extra pressure onto an already stretched NHS, which is considered to be in the midst of its worst winter on record.
The latest data from the RCGPs' Research and Surveillance Centre (RSC) includes over 1.7m patients - its biggest ever sample.
Overall 53.1 people per 100,000 presented with an influenza like illness (ILI) in the second week of the year, compared to 37.3 in the first.
The Midlands and East England, which includes Birmingham, Norwich and Nottingham, were worst affected (57.9) - an increase from 35.5.
Next was North England including Manchester, York and Newcastle, which was up from 34.5 to 57.3, followed by South England, which covers Bristol, Portsmouth and Canterbury, that saw a rise from 45.3 to 54.3. London increased from 30.3 to 42.1.
The rate is much higher than the same week last year (20.3) but this could be explained by strains generally peaking at different times.
Prof Stokes-Lampard said: "Wintertime always brings challenges for the health service, and GP practices have prepared well in order to deliver the best possible care for patients.
"But patients can also help in keeping themselves safe and well during the cold weather.
"The best prevention for flu, other than observing good hygienic practices, such as regular hand washing, is for people, particularly those in at-risk groups, including patients with long-term conditions and pregnant women, to get their flu jab.
"It is not too late to receive some benefit from vaccination.
"If someone does have the flu, unfortunately there is no cure, but patients can assist their own recovery through taking plenty of rest and drinking lots of fluids as it is easy to become dehydrated.
"Fevers and muscle ache, which are often symptoms of flu can also be improved with paracetamol or ibuprofen, if appropriate.
"We do encourage patients who are ill to think hard about whether they do need to see a GP - not just in terms of reducing pressures on the NHS, but to minimise the possibility of passing viruses, such as flu, to other people, particularly in at-risk groups, such as those with long-term conditions or pregnant women.
"The College's '3 before GP' advice asks patients whether self-care is an option in the first instance; whether advice from a reputable online UK source, such as NHS Choices, could help; or whether they could seek advice from a pharmacist, before booking an appointment with their GP."
Rates of other common winter illnesses, which saw a sharp rise in last week's figures, largely levelled out, according to the latest weekly report.
Acute bronchitis fell from 146.6 to 130.1 per 100,000, asthma increased from 16.2 to 17.7, the common cold was unchanged at 142.6 compared with 142.3 and respiratory system diseases went up slightly from 463.2 to 467.6.
Prof Simon de Lusignan, medical director at the RSC, added: "We are seeing numbers of presentations of respiratory conditions change little this week, but unsurprisingly given what we have been hearing anecdotally from GPs, rates of influenza-like illness have risen again.
"Whilst flu rates in primary care are still within what we term the 'medium threshold', the virus does seem to be affecting patients aged over 65 most, with rates moving into the 'very high threshold'.
"As ever, flu is unpredictable so it remains impossible to speculate how rates will change in the coming weeks - they may increase further, they may level out or even decline.
"The RSC will continue to compile data, so that we can inform preparedness plans for next year as comprehensively as possible."