It had a slow start but now the summer is making one last effort with the warmest spell in September for seven years.

A mini-heatwave is set to bring temperatures of 30C (86F) today, beating the highs that southern England enjoyed yesterday.

The two-day heat blast is the culmination of the steadily rising mercury over the past few days.

Looking good: Flora celebrated the return of their iconic sunflower logo by creating a field of sunflowers at Potters Fields Park in Central London, with Tower Bridge and the River Thames in the background

Splashing about: Rhiannon Fletcher and Megan Noble (left and right, in left photo), and Joanna Rokosz and Aleksandra Susek (left and right, in right photo) enjoy the beautiful weather on Bournemouth beach in Dorset

Flag flying: A woman walks through Victoria Tower Gardens in Central London. The warm weather will fade away by Friday, with rain forecast

Met Office forecaster Helen Chivers said the South East of England will have the best weather today.

‘Temperatures there could reach 30C (86F) in parts of Kent and Sussex,’ she said. ‘The further west and north you go, we’re looking at 19C (66F) to 21C (70F).’

It follows yesterday when the South East had hotspots of up to 29C (84F), while England and Wales  generally hit the mid-20s.

But the warm spell will be all too brief and over by the weekend. Temperatures could plunge by 10C or more tomorrow as thunder and heavy rain push out the blue skies.

Sizzling in the sun: Friends Jo Holgate (left) and Tasha Cox (right), both 24, from Portsmouth, soak up the sunshine on Southsea Common in Hampshire

King of the sandcastle: Gemma Healey (left), five, of Southampton, and Teigan Rainsbury (right), two, of Andover, Hampshire, have fun playing on Bournemouth beach

Oh I do like to be beside the sea: Twins James and Grace Dunning, four, from Basingstoke, Hampshire, made the most of the warm weather on Bournemouth beach

Lined up: Czech students (left-to-right) Renata Svetlikova, 23, Veronika Vrablova, 21, Gabika Kuciakova, 21, Jana Pekarova, 18, and Eliska Splichalova, 20, were pictured on Bournemouth beach

Posing up: These Czech students who had travelled to Bournemouth to pick blueberries were pictured enjoying the hot September sun on the town's popular beach

Beach time: Kelly Davis (right) with her 16-month-old daughter Maisy Cochrane (left) and friend Suzanne Allerdyce (centre) enjoy the sun on Newcastle's Quayside as the hot weather continues

Sun is shining: People relax and enjoy the weather in Castle Park, Bristol, with temperatures in the upper 20s

Lovely day: People enjoy eating and drinking outside at The Tiger Inn pub in Beachy Head, East Sussex

Sailing: The Ellis family look at radio controlled boats on the Lake at Sefton Park in Liverpool, which English Heritage has reclassified to a grade 1 park, as the hot weather continues across the country

Looking out: A couple enjoy the sun on a hot day for Britain while sitting on a bench at a beach in Sussex

Apple harvest: Davina Roberts, 23, orchard supervisor at Hill Farm, near Winchester, Hampshire, picks Discovery apples on the first day of this year's harvest, which will continue into early November

Cooling off: The deer at Bushy Park in Richmond, south-west London, have been enjoying the hot weather

Floating: Boaters making the most of the last of the summer sun on the River Wye at Ross on Wye in Herefordshire at lunchtime yesterday

Miss Chivers added: ‘The cloud and rain that’s been in Northern Ireland and Scotland is going to creep south-eastwards. On Friday and into the weekend, we see things change.’

A low pressure system moving in from France will worsen this band of bad weather tomorrow.

‘There will be a lot of cloud around England and Wales, and rain on and off during the day, some heavy. We could also hear thunder,’ said Miss Chivers.

‘That carries on into the weekend. So, quite a change. Temperatures are going to drop.’

The South will be the warmest at  21C (70F) on Saturday but forecasters hope for brighter skies on Sunday.

Getting wet: Molly Pearse, four, of Buckinghamshire, plays on Bournemouth beach as sunseekers make the most of the weather before rain arrives at the weekend

Flat out: A businessman sleeps in the sunshine in a park in Central London. The late summer fine weather is set to continue today

A picture: An artist paints on the banks of the River Thames under the shadow of Windsor Castle as the warm weather continues

Taking a break: A woman eats her lunch and reads a book while sitting down at Victoria Embankment Gardens in Central London

Making the most of it: A woman sunbathes in a park in Central London. The late summer fine weather is set to continue across Britain

How to spend a lunchtime: People relax in Victoria Embankment Gardens in Central London as they make the most of being able to sit outside on the grass

On the water: Two people on sailing boats enjoyed the weather in Sussex as Britain basked in sunshine for two more days before the rain begins

Bright: City workers in London take time out during lunch to view the hot rays of light coming from the new Walkie Talkie tower in Central London

Oh what a beautiful day: People relax in a park in Central London. The UK Met Office forecast temperatures across London and the south east reaching up to 30C

Nice day: People relax in Victoria Embankment Gardens in London. Much of Britain is experiencing higher than average temperatures

Having a chat: Two women sit down and eat lunch at Victoria Embankment Gardens in Central London, which was a picture postcard sight in the capital

Daredevils: People were jumping off rocks out in the sea near Bournemouth beach in Devon as they made the most of the beautiful weather

Resting: A man lies down and relaxes in Victoria Embankment Gardens in Central London. Much of Britain is experiencing higher than average temperatures

Seagulls: A couple sit down and two men walk along Brighton beach in East Sussex as Britain enjoys excellent weather for September

Digging: The heatwave continues on Bournemouth beach today as sunseekers make the most of the weather before the rain arrives at the weekend

Spade: Kelly Davis (right) with her daughter Maisy Cochrane (left) and friend Suzanne Allerdyce (centre) enjoy the sun on Newcastle's Quayside

Holding it: Warm rays casting across fields in Teesdale, County Durham as the sun sets beautifully last night

Eerie start: Drilling platforms at a repair yard and Hartlepool Nuclear Power Station are masked this morning by pre-dawn mist rolling in and out of Seal Sands at Teesmouth between Hartlepool and Redcar

Early on: The sun rises over Seal Sands in Hartlepool, ahead of a hot day

Sunrise: Visitors to Glastonbury Tor take a photographs of St Michael's Tower, a ruined 14th-century church tower, as the sun rises and begins to clear the early morning mist and fog near the town of Glastonbury

Special moment: A dog walker (left) takes in the view at the top of Glastonbury Tor as the rising sun begins to clear the early morning mist, and a visitor (right) meditates beside St Michael's Tower

Starting out: Sheep graze beside the 14th-century St Michael's Tower, on Glastonbury Tor as the sun rises and begins to clear the early morning mist and fog