He was best known for the neofuturistic Selfridges Building in Birmingham, England, and the Media Centre at Lord's Cricket Ground in London.

[5][6] In the wake of the Prague Spring, the Soviet invasion of Czechoslovakia, he escaped to London in September 1968 with fellow architect Jaroslav Vokoun carrying only US$100 and a few pairs of socks.

In England, Kaplický first worked for Denys Lasdun and Partners (1969–1971), then obtained employment with the office of Renzo Piano and Richard Rogers (1971–1973), where he worked on DRU extension at Aybrook Street, London and later helping to develop the design for the Centre Georges Pompidou (constructed 1971–1977) in Paris by joining the team of more than 30 strong.

Among the drawings he made were structures orbiting the Earth built by robots, weekend houses resembling survival capsules that could be transported by helicopter, and home interiors that could be manipulated.

In the 1980s his design for the Grand Buildings in Trafalgar Square, London, was a free-form monocoque structure pierced by portholes; it lost to a more conventional reconstruction of an Edwardian facade.

[11] Although Kaplický was a finalist for the Prince Philip Prize for designer of the year in 1991, for the first 15 years of its existence Future Systems, he received few commissions until 1994, where the company was commissioned to build the new media centre at Lord's Cricket Ground which eventually won the Royal Institute of British Architects (RIBA) Stirling Prize – considered the most prestigious architecture award in the UK – in 1999 and the World Architecture Awards in 2001.

[9] Kaplický considered the media centre "my favourite creation", saying, "It is something which was revolutionary in many areas – a real technical achievement – but above all, the people operating inside it have said: 'We love it,' and that's great.

President of the Czech Republic Václav Klaus was overheard saying he would be willing to prevent the building going ahead with his own body; his spokesman later clarified it was an off-hand remark that had not been meant to be taken seriously.

"[6] Although the design was eventually dropped, Kaplický remained hopeful that the building would be built through funds from a private foundation established for this purpose.

On 14 January 2009, hours after the birth of his daughter Johanna Kaplická, he collapsed on a street in Prague near Vítězné náměstí (Victory Square) with heart failure and could not be revived by emergency services.