A gang of thieves broke into an upmarket central London jewellers and stole an estimated £500,000 of gems and valuables in an audacious heist, police said on Wednesday.

The burglary at George Attenborough and Son jewellers happened over the weekend and has led to claims the thieves must have tunnelled in, sparking comparisons to the 2015 heist in Hatton Garden. Police will only say that the thieves broke in through a wall to gain access to the jewels inside, and that the burglary lacked the sophistication of the Hatton Garden heist.

Scotland Yard’s Flying Squad are hunting those behind the heist on the shop, which specialises in diamond rings, necklaces, pearls and other expensive jewellery.

For part of the weekend a half-marathon was taking place close to the jewellers, which is on Fleet Street in central London. The store is shut over the weekend and is in an area where most shops and offices would also be closed outside normal working hours.

Det Supt Simon Moring, leading the investigation, said: “This was an audacious burglary, and there are elements that appear to have been planned with some precision by the suspects. They broke through a wall in order to gain access to the store. At this stage we are not releasing any further details about the methods used by the suspects.

“It is nowhere near the sophistication of some previous burglaries dealt with by the Flying Squad, including high-profile crimes such as the Hatton Garden burglary in 2015.”

Moring added:“The estimated loss is £500,000. This is a theft of high value which warrants thorough and determined investigation. We know that the raid took place between Saturday 23 [March] and Sunday 24 March. I would urge people who were in the area to think back. It may be that you saw something and now realise it may have been out of place. If this is the case, please make contact with us, even if that is anonymously.”

Detectives were securing and studying footage from CCTV systems in the area for clues. A breakthrough via CCTV ultimately snared the Hatton Garden gang.

Unlike the 2015 heist, establishing the estimated value of the items stolen in the weekend raid was relatively simple. In Hatton Garden, safety deposit boxes kept by private clients were broken into and their contents stolen. Establishing their value was a long and complex process, as well as working out what exactly was stolen, with some owners declining to come forward.

George Attenborough and Son Jewellers would have had a better idea of what they had in stock, what was missing and an estimate of its worth.

As well as breaking into the shop, which was established in 1843 and describes itself as “one of the United Kingdom’s most iconic, traditional jewellers”, the thieves would have had to bypass alarms and security once inside.

The store’s website says: “Our array of diamond and gem-set jewellery remains locked into the world of fine luxury goods where style and form remains timeless and non-dating.” It also values jewellery for insurance purposes, taking a commission of 1% of the value plus a £25 handling fee.